Method for generating preamble, method for configuring preamble and equipment thereof, random access method, device, user equipment and base station

ABSTRACT

The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. The present application discloses a method for generating a preamble, comprising the following steps of: receiving dedicated preamble configuration information and random access preamble configuration information, wherein the dedicated preamble configuration information comprises root sequence configuration information and/or cyclic shift value configuration information; determining dedicated root sequence configuration information, dedicated cyclic shift value configuration information and dedicated preamble index according to the dedicated preamble configuration information and random access preamble configuration information.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 371 National Stage of International ApplicationNo. PCT/KR2018/007218, filed Jun. 26, 2018, which claims priority toChinese Patent Application No. 201710495615.X, filed Jun. 26, 2017,Chinese Patent Application No. 201711022900.6, filed Oct. 26, 2017,Chinese Patent Application No. 201711144592.4, filed Nov. 16, 2017, andChinese Patent Application No. 201810028303.2, filed Jan. 11, 2018, thedisclosures of which are herein incorporated by reference in theirentirety.

BACKGROUND 1. Field

The present invention relates to the technical field of wirelesscommunication, and in particular to a method for generating preamble, amethod for configuring preamble and equipment thereof, a random accessmethod, device, user equipment and base station.

2. Description of Related Art

To meet the demand for wireless data traffic having increased sincedeployment of 4G communication systems, efforts have been made todevelop an improved 5G or pre-5G communication system. Therefore, the 5Gor pre-5G communication system is also called a ‘Beyond 4G Network’ or a‘Post LTE System’. The 5G communication system is considered to beimplemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, soas to accomplish higher data rates. To decrease propagation loss of theradio waves and increase the transmission distance, the beamforming,massive multiple-input multiple-output (MIMO), Full Dimensional MIMO(FD-MIMO), array antenna, an analog beam forming, large scale antennatechniques are discussed in 5G communication systems. In addition, in 5Gcommunication systems, development for system network improvement isunder way based on advanced small cells, cloud Radio Access Networks(RANs), ultra-dense networks, device-to-device (D2D) communication,wireless backhaul, moving network, cooperative communication,Coordinated Multi-Points (CoMP), reception-end interference cancellationand the like. In the 5G system, Hybrid FSK and QAM Modulation (FQAM) andsliding window superposition coding (SWSC) as an advanced codingmodulation (ACM), and filter bank multi carrier (FBMC), non-orthogonalmultiple access (NOMA), and sparse code multiple access (SCMA) as anadvanced access technology have been developed.

The Internet, which is a human centered connectivity network wherehumans generate and consume information, is now evolving to the Internetof Things (IoT) where distributed entities, such as things, exchange andprocess information without human intervention. The Internet ofEverything (IoE), which is a combination of the IoT technology and theBig Data processing technology through connection with a cloud server,has emerged. As technology elements, such as “sensing technology”,“wired/wireless communication and network infrastructure” “serviceinterface technology”, and “Security technology” have been demanded forIoT implementation, a sensor network, a Machine-to-Machine (M2M)communication, Machine Type Communication (MTC), and so forth have beenrecently researched. Such an IoT environment may provide intelligentInternet technology services that create a new value to human life bycollecting and analyzing data generated among connected things. IoT maybe applied to a variety of fields including smart home, smart abuilding, smart city, smart car or connected cars, smart grid, healthcare, smart appliances and advanced medical services through convergenceand combination between existing Information Technology (IT) and variousindustrial applications.

In line with this, various attempts have been made to apply 5Gcommunication systems to LDT networks. For example, technologies such asa sensor network, Machine Type Communication (MTC), andMachine-to-Machine (M2M) communication may be implemented bybeamforming, MIMO, and array antennas. Application of a cloud RadioAccess Network (RAN) as the above-described Big Data processingtechnology may also be considered to be as an example of convergencebetween the 5G technology and the EDT technology.

The rapid development of information industry, particularly theincreasing demand from the mobile Internet and the Internet of Things(IoT), brings about unprecedented challenges in the future mobilecommunications technology. According to the ITU-R M. [IMT. BEYOND 2020.TRAFFIC] issued by the International Telecommunication Union (ITU), itcan be expected that, by 2020, mobile services traffic will grow nearly1,000 times as compared with that in 2010 (4G era), and the number ofuser equipment connections will also be over 17 billion, and with a vastnumber of IoT equipments gradually expand into the mobile communicationnetwork, the number of connected equipments will be even moreastonishing. In response to this unprecedented challenge, thecommunications industry and academia have prepared for 2020s bylaunching an extensive study of the fifth generation of mobilecommunications technology (5G). Currently, in ITU-R M. [IMT, VISION]from ITU, the framework and overall objectives of the future 5G havebeen discussed, where the demands outlook, application scenarios andvarious important performance indexes of 5G have been described indetail. In terms of new demands in 5G, the ITU-R M. [IMT. FUTURETECHNOLOGY TRENDS] from ITU provides information related to the 5Gtechnology trends, which is intended to address prominent issues such assignificant improvement on system throughput, consistency of the userexperience, scalability so as to support IoT, delay, energy efficiency,cost, network flexibility, support for new services and flexiblespectrum utilization, etc.

The performance of random access directly influences the user'sexperience. For a conventional wireless communication system, forexample, LTE or LTE-Advanced, a random access process is used in variousscenarios such as establishment of an initial link, cell handover,reestablishment of an uplink, Radio Resource Control (RRC) connectionreestablishment, and is classified into contention-based random accessand contention-free random access, depending upon whether a userexclusively occupies preamble sequence resources. Since, for thecontention-based random access, each user selects a preamble sequencefrom same preamble sequence resources when trying to establish anuplink, there may be a case in which multiple users select and transmita same preamble sequence to the base station. Therefore, the collisionresolution mechanism becomes an important research direction in therandom access. How to reduce the collision probability and how toquickly solve a collision that has occurred are key indicatorsinfluencing the random access performance.

The contention-based random access process in LTE-A includes four steps,as shown in FIG. 1. In the first step, a user randomly selects onepreamble sequence from a preamble sequence resource pool and transmitsthe preamble sequence to a base station. The base station performscorrelation detection on the received signal, so as to identify thepreamble sequence transmitted by the user. In the second step, the basestation transmits a Random Access Response (RAR) to the user, the RARcontaining an identifier of a random access preamble sequence, a timingadvance instruction determined according to a time delay between theuser and the base station, a Cell-Radio Network Temporary Identifier(C-RNTI), and time-frequency resources allocated for the user to performuplink transmission next time. In the third step, the user transmits athird message (Msg3), to the base station according to the informationin the RAR. The Msg3 contains information such as a user equipmentterminal identifier and an RRC link request, wherein the user equipmentterminal identifier is an identifier that is unique to the user and usedfor resolving collision. In the fourth step, the base station transmitsa collision resolution identifier to the user, the collision resolutionidentifier containing a user equipment identifier corresponding to auser who wins in the collision/solution. The user upgrades TC-RNTI toC-RNTI upon detecting its identifier, and transmits an Acknowledgement(ACK) signal to the base station to complete the random access processand waits for the scheduling of the base station. Otherwise, the userwill start a new random access process after a certain delay.

For a contention-free random access process, since the base station hasknown the identifier of the user, it can allocate a preamble sequence tothe user. Thus, when transmitting a preamble sequence, the user does notneed to randomly select a sequence, and instead, it use the allocatedpreamble sequence. Upon detecting the allocated preamble sequence, thebase station will transmit a corresponding random access response, therandom access response including information such as timing advance anduplink resource allocation. Upon receiving the random access response,the user considers that the uplink synchronization has been completed,and waits for the further scheduling of the base station. Therefore, thecontention-free random access process contains only two steps: a firststep of transmitting a preamble sequence, and a second step oftransmitting a random access response.

The random access process in LTE is applicable to the followingscenarios:

1. initial access under RRC_IDLE;

2. reestablishment of RRC connection;

3. cell handover;

4. the downlink data arrives and a random access process is requested(when the uplink is nonsynchronous) in an RRC connected state;

5. the uplink data arrives and a random access process is requested(when the uplink is nonsynchronous or no source is allocated for ascheduling request in a PUCCH resource) in an RRC connected state; and

6. positioning.

In the LTE, the six scenarios use the same random access steps. In the5G standard research, a downlink transmission beam and available randomaccess resources (random access channel resources and/or random accesspreamble resources) will be bound, so that the base station can acquirean available downlink transmission beam selected by a UE through adetected preamble from the UE and/or time-frequency resources in whichthe detected preamble is located. In a beamforming system, for the beamfailure recovery, there are four aspects: beam failure detection, newcandidate beam identification, Beam Failure Recovery Request (BFRQ)transmission, and UE monitors gNB response for beam failure recoveryrequest. Wherein, when the UE needs to transmit a beam failure recoveryrequest, the way similar to random access may be used to inform the basestation of its own beam failure request demand and explicitly orimplicitly inform the base station of similar available candidate beams.But it is considered that the number of the users in the connected stateis large and resources necessary for beam failure recovery may be more,so that traditional method for configuring contention-free random accesspreambles may not satisfy the demand.

In the existing 5G standard discussion, communication systems adopt abeamforming mode. However, when a UE detects that there is a beamfailure, that is, when the quality of a downlink beam has not satisfieda certain condition, the UE needs to recover the beam failure.Meanwhile, the UE needs to inform a base station of new availabledownlink transmission beams or whether there are new available downlinktransmission beams. The system will configure dedicated resources for abeam failure recovery request for the UE, including preamble resourcesand time-frequency resources. However, if random access preambleresources in the preamble resources are reused, a problem ofinsufficient capacity may occur, which is not enough to provide theusers in the connected state with sufficient preamble resources.

Random access procedure is an important way to establish connectionbetween the terminal device and the base station in the system. Inlong-term evolution LTE technology, regardless of whether it is acontention-based random access procedure, a random access preamble needsto be transmitted in a Physical Random Access Channel (PRACH). In LTE,the number of preambles that can be used in each cell is fixed at 64. In5G, the number of terminal devices in the cell will increase as thecells are denser and the types of supported terminal devices are morediverse. Therefore, it is necessary to increase the number of preamblesto improve the performance of random access.

In the existing LTE technology, the total number of random accesspreamble is fixed at 64. For 5G system, a fixed number of preambles isslightly insufficient for some scenarios, while for other scenarios, afixed number of preambles are somewhat redundant. Therefore, theconfiguration manner of the number of preambles in the prior art lacksflexibility and is difficult to apply to all application scenarios.

In the LTE, the above-mentioned six scenarios use the same random accesssteps. In a new communication system, a user equipment performing randomaccess may be able to transmit multiple preambles in one random accessattempt in order to increase the probability of accessing the system.However, how to determine beams, preamble sequences and methods forcontrolling the random access power and a power ramp used by the userequipment in a scenario where multiple preambles may be transmittedneeds to be solved, so that the user equipment may normally access thesystem by a method for multiple preambles based random access.

For a new system, the user equipment may perform multiple preamblesbased random access, so that the probability of accessing the system bya user in one attempt may be increased. However, unlike the existingrandom access method based on a single preamble, during the transmissionof multiple preambles, the user equipment needs to clearly determinesequence choices and beam choices for transmitting multiple preambles,random access resources corresponding to the determined downlink beamsand the method for controlling the random access power and the powerramp. Otherwise, the user equipment cannot perform the random access ina normally controllable manner.

Compared with the existing LTE system, 5G will introduce a systemoperating in a high frequency band to improve system data transmissionefficiency and spectrum utilization. In order to withstand thesignificant path loss in high frequency band wireless channels, wirelesscommunication systems operating in high frequency bands requiremulti-beam operation to improve system performance with beamforming gaindue to correct beam pairing. Therefore, for multi-beam systems, theaccuracy of beam pairing will significantly affect system performance.When the terminal finds that the system performance is degraded due toinaccurate beam pairing, the beam recovery procedure is triggered.Specifically, the terminal first detects a beam pairing failure; if abeam pairing failure is detected, a candidate beam is determinedaccording to a beam-related reference signal; then a beam failurerecovery request is initiated, and a corresponding request is initiatedto a base station through a dedicated channel or resource; after thebeam failure recovery request is initiated, the terminal detects thecorresponding beam failure recovery request response. The aboveprocedure can be described by FIG. 1.

SUMMARY

The terminal may initiate a beam failure recovery request on a physicalrandom access channel, an uplink control channel, or a channeltime-frequency resource similar to a physical random access channel.Considering that the beam failure recovery needs to be completed with ashort delay, the beam failure recovery request needs to be transmittedin a contention-free manner. That is, the allocation of resources(including time-frequency resources and sequence resources) used for thebeam failure recovery request is dedicated to the terminal.

Since the existing beam failure recovery procedure is contention-free,how to allocate distinguishable resources (time-frequency resources andsequence resources) for beam failure recovery procedure to the differentterminals with low signaling overhead is a problem that needs to beconsidered.

An objective of the present invention is to overcome the deficiency inthe prior art and to provide a method for configuring information.Dedicated resources for beam failure recovery (including preambleresources and time-frequency resources) are configured for a UE toperform beam failure recovery, wherein the preamble resources include adedicated cyclic shift indication, root sequence indication, etc.According to the present invention, it is further provided that how theUE acquire preamble resources for beam failure recovery by the acquiredconfiguration information of random access preamble resources(contention-based and contention-free random access preamble resources)and dedicated resource information for beam failure recovery.

In order to achieve the above object, the present invention provides amethod for generating a preamble, which includes the following steps:

receiving dedicated preamble configuration information and random accesspreamble configuration information, wherein the dedicated preambleconfiguration information comprises root sequence configurationinformation and/or cyclic shift value configuration information;

determining dedicated root sequence configuration information, dedicatedcyclic shift value configuration information and dedicated preambleindex according to the dedicated preamble configuration information andrandom access preamble configuration information;

generating a dedicated preamble according to the determined dedicatedroot sequence configuration information, dedicated cyclic shift valueconfiguration information and dedicated preamble index; and

transmitting the dedicated preambles on dedicated time-frequencyresources configured by a base station.

Preferably, the dedicated preamble configuration information comprises adedicated preamble index.

Preferably, the random access preamble configuration informationcomprises a root sequence index of random access preamble and cyclicshift value configuration of the random access preamble, and the randomaccess preamble configuration information further comprises at least oneof the following: number of preambles for contention-based randomaccess, number of preambles for contention-free random access and thetotal number of preambles for random access.

Preferably, the step of determining root sequence index of dedicatedpreambles comprises one of the following steps of:

using the root sequence index of the random access preamble in randomaccess preamble configuration information as the root sequence index ofthe dedicated preamble;

or, indicating to generate the root sequence index of the dedicatedpreamble according to the root sequence index of the random accesspreamble in the random access preamble configuration information and anoffset in dedicated preamble resource configuration information;

or, using the root sequence index of the dedicated preamble in thededicated preamble resource configuration information.

Preferably, the step of determining the cyclic shift value configurationof the dedicated preamble comprises one of the following steps of:

using the cyclic shift value configuration of the random access preamblein random access preamble configuration information as the cyclic shiftvalue configuration of the dedicated preamble;

acquiring the cyclic shift value configuration of the dedicated preambleaccording to the cyclic shift value of the random access preamble in therandom access preamble configuration information and scale factorconfiguration in dedicated preamble resource configuration information;

acquiring the cyclic shift value configuration of the dedicated preambleaccording to the cyclic shift values of random access preamble in therandom access preamble configuration information and offsetconfiguration in the dedicated preamble resource configurationinformation; and

using the cyclic shift value configuration of the dedicated preamble inthe dedicated preamble resource configuration information.

Preferably, the step of determining the dedicated preamble indexcomprises one of the following steps of:

determining the dedicated preamble index according to a preamble indexand offset configuration in dedicated preamble resource configurationinformation; and

using the dedicated preamble index in the dedicated preamble resourceconfiguration information.

Preferably, the step of generating dedicated preamble according to theroot sequence index of the dedicated preamble, cyclic shift valueconfiguration of the dedicated preamble and the dedicated preamble indexcomprises one of the following steps of:

generating the dedicated preamble sequence allocated by a base stationaccording to the cyclic shift value indicated by the determined cyclicshift value configuration of the dedicated preamble and the preambleindex indicated by the determined dedicated preamble index, according tothe preamble root sequence indicated by the determined dedicated rootsequence index and starting from the starting point of the rootsequence;

generating the dedicated preamble sequence allocated by the base stationaccording to the determined cyclic shift value of the dedicated preambleand determined dedicated preamble index indication, according to thepreamble root sequence indicated by the determined dedicated rootsequence index and starting from a cyclic shift of the firstcontention-free random access preamble; and

generating the dedicated preamble sequence allocated by the base stationaccording to the determined cyclic shift value of the dedicated preambleand the determined dedicated preamble index indication, according to thepreamble root sequence indicated by the determined dedicated rootsequence index and starting from a cyclic shift of a contention-freerandom access preamble configured by the base station.

In order to achieve the above object, the invention also provides amethod for configuring a preamble, which comprises the following steps:

transmitting random access preamble configuration information anddedicated preamble configuration information, wherein the dedicatedpreamble configuration information comprises root sequence configurationinformation and/or cyclic shift value configuration information; and

detecting a preamble on allocated dedicated time-frequency resources.

Preferably, the random access preamble configuration informationcomprises a root sequence index indication of a preamble for randomaccess and cyclic shift value configuration for random access, and therandom access preamble configuration information further comprises atleast one of the following: number of preambles for contention-basedrandom access, number of preambles for contention-free random access andthe total number of preambles for random access.

Preferably, the root sequence configuration information comprises adedicated root sequence index or root sequence offset configuration.

Preferably, the cyclic shift value configuration information comprisesdedicated preamble cyclic shift value configuration information or ascale factor configuration or an offset configuration.

Preferably, the dedicated preamble configuration information comprisespreamble index configuration information.

Preferably, the preamble index configuration information comprises adedicated preamble index and/or an offset of a preamble index.

The present invention further provides a User Equipment (UE), comprisingthe following modules:

a preamble resource configuration information acquisition module,configured to receive random access preamble configuration and dedicatedpreamble configuration information;

a dedicated preamble determination module, configured to determine rootsequence configuration information of a dedicated preamble, dedicatedcyclic shift value configuration information and dedicated preambleindex;

a dedicated preamble generation module, configured to generate thededicated preamble according to the determined root sequenceconfiguration information of the dedicated preamble, the determinedcyclic shift value configuration information and the determined preambleindex; and

a dedicated preamble transmitting module, configured to transmit thededicated preamble on dedicated time-frequency resources configured by abase station.

The present invention further provides a base station equipment,comprising the following modules:

a configuration information transmitting module, configured to transmitrandom access preamble configuration information and dedicated preambleconfiguration information; and

a preamble detection module, configured to detect the dedicated preambleon the configured dedicated time-frequency resources.

Compared with the prior art, the technical effects of the presentinvention include, but are not limited to: a gNB configures preambleresource information for a beam failure recovery request UE and informthe UE of the information; after the UE acquires the configurationinformation, the preamble sequence for a beam failure recovery requestof a user is determined finally by preamble configuration informationfor a beam failure recovery request and random access preambleconfiguration information which may be used. It is convenient for aterminal to carry out a beam failure recovery request by transmitting apreamble.

The configuration manner of the number of preambles in the existing LTEtechnology lacks flexibility and is difficult to adapt to moreapplication scenarios and more terminal device numbers in 5G. Therefore,in view of this problem, the present disclosure provides a flexiblepreambles configuration manner. The number of preambles is configured inan explicit or implicit manner so that the number of preambles allocatedto the terminal device may be more flexibly configured according tofactors such as application scenarios and the number of loads.

One aspect of the present disclosure provides a random access methodcomprising: obtaining a maximum number of preambles; generating a randomaccess preamble according to the maximum number of preambles andpreamble configuration information; and transmitting the random accesspreamble on a random access channel.

According to the embodiments of the present disclosure, the obtaining amaximum number of preambles comprises: obtaining the maximum number ofpreambles according to initial access configuration information orrandom access configuration information.

According to the embodiments of the present disclosure, the obtaining amaximum number of preambles comprises: obtaining configurationinformation of the maximum number of preambles, and determining themaximum number of preambles according to the configuration informationof the maximum number of preambles.

According to the embodiments of the present disclosure, the methodfurther comprises obtaining the configuration information of the maximumnumber of preambles from at least one of the following:

random access configuration information; and

preamble configuration information.

According to the embodiments of the present disclosure, the obtaining amaximum number of preambles comprises:

determining the maximum number of preambles according to pre-definedsystem information and an association between the pre-defined systeminformation and the maximum number of preambles.

According to the embodiments of the present disclosure, the pre-definedsystem information comprises at least one of the following:

preamble format;

sub-carrier spacing of random access channel;

the repetition number of sequences within one preamble;

the maximum value of a plurality of numbers of down-link signalsassociated to a same random access occasion; and

the number of down-link signals associated to a currently selectedrandom access occasion.

According to the embodiments of the present disclosure, the sub-carrierspacing of random access channel is included in the random accessconfiguration information or the preamble format.

According to the embodiments of the present disclosure, the methodfurther comprises: detecting a random access response, and determiningthe random access preamble according to a preamble identifier in therandom access response.

According to the embodiments of the present disclosure, the determiningthe random access preamble according to the preamble identifier in therandom access response comprises:

determining the preamble identifier in the random access responseaccording to a predetermined indication manner of the preambleidentifier; and

determining the random access preamble according to the preambleidentifier.

According to the embodiments of the present disclosure, the indicationmanner of the preamble identifier comprises any one of the following:

indicating a number of bits of the preamble identifier according to themaximum number of preambles, and indicating the preamble identifieraccording to the number of bits of the preamble identifier;

indicating the number of bits of the preamble identifier according to amaximum value of a plurality of maximum numbers of preambles, andindicating the preamble identifier according to the number of bits ofthe preamble identifier; and

indicating the preamble identifier according to down-link signalindication bits indicating the down-link signals and pre-definedpreamble identifier bits.

According to the embodiments of the present disclosure, the indicatingthe preamble identifier further comprises:

indicating the transmitted random access preamble in the random accessresponse by the pre-defined preamble identifier bits and the additionaldown-link signal indication bits; or

indicating the transmitted random access preamble by the pre-definedpreamble identifier bits in the random access response and theadditional down-link signal indication bits for calculating a randomaccess radio network temporary identifier RA-RNTI.

According to the embodiments of the present disclosure, the down-linksignal comprises any one of a synchronization signal block and a channelstate information reference signal.

Another aspect of the present disclosure is to provide a random accessmethod comprising: transmitting configuration information of a maximumnumber of preambles; detecting a random access preamble; andtransmitting a random access response.

According to the embodiments of the present disclosure, the transmittingthe configuration information of the maximum number of preamblescomprises: transmitting at least one of the following informationincluding the configuration information of the maximum number ofpreambles:

random access configuration information; and

preamble configuration information.

Another aspect of the present disclosure provides a terminal comprisinga processor and a memory storing instructions that, when executed by theprocessor, cause the processor to perform corresponding methodsdescribed in the embodiments of the present disclosure.

Another aspect of the present disclosure provides a base stationcomprising a processor and a memory storing instructions that, whenexecuted by the processor, cause the processor to perform correspondingmethods described in the embodiments of the present disclosure.

Another aspect of the present disclosure provides a machine readablemedium storing instructions that, when executed by a processor, causethe processor to perform the corresponding methods described in theembodiments of the present disclosure.

The manner provided in the embodiments of the present disclosure mayflexibly configure the maximum number of preambles supported by thesystem, so that the number of preambles allocated to the terminal devicemay be more flexibly configured according to factors such as applicationscenarios and the number of loads.

An objective of the present disclosure is to solve at least one of theabove technical defects, particularly the random access problem ofmultiple preambles.

The present disclosure provides a random access method, including stepsof:

determining, by a User Equipment (UE), random access resources; and

determining a preamble sequence and an uplink transmitting beam fortransmitting multiple preambles to perform multiple preambles basedrandom access, when it is determined according to the random accessresources that multiple preambles based random access is performed.

The method further includes the step of:

determining, according to a determined number of downlink transmittingbeams and a number of preambles that may be transmitted by each downlinktransmitting beam, a preamble power ramping counter and/or a preambletransmission counter; and

the step of performing multiple preambles based random access includes:

performing the multiple preambles based random access according to thedetermined preamble sequence and uplink transmitting beam fortransmitting the multiple preambles and at least one of the followings:a counting result of the preamble power ramping counter and a countingresult of the preamble transmission counter.

The method for determining the preamble sequence for transmittingmultiple preambles includes:

selecting one preamble sequence for each of the determined downlinktransmitting beams, and transmitting the preamble corresponding to thedownlink transmitting beam by using the selected preamble sequence; or,

selecting one preamble sequence, and transmitting all preambles in onerandom access attempt by using the selected preamble sequence; or,

determining a preamble sequence configured in the random accessresources as the preamble sequence for transmitting the multiplepreambles.

The method for determining the uplink transmitting beam for transmittingthe multiple preambles includes: determining the uplink transmittingbeam for the multiple preambles corresponding to one downlinktransmitting beam, and determining, according to the determined uplinktransmitting beams, the uplink transmitting beam for the multiplepreambles corresponding to other downlink transmitting beam; or,

randomly determining the uplink transmitting beams used by the preamblescorresponding to all downlink transmitting beams with equal probability.

The step of determining the preamble power ramping counter includes:

determining one preamble power ramping counter for each of thedetermined downlink transmitting beams, wherein multiple preamblescorresponding to the same downlink transmitting beam share the samepreamble power ramping counter; or,

determining one preamble power ramping counter for each preambledetermined to be transmitted; or,

determining one preamble power ramping counter for all preamblesdetermined to be transmitted.

When the UE has N determined downlink transmitting beams and each of thedownlink transmitting beams corresponds to M preambles,

in a case where the multiple preambles corresponding to each of thedownlink transmitting beams share the same preamble power rampingcounter, when the UE performs a new random access attempt during a samerandom access process, the method for determining the counting result ofthe preamble power ramping counter includes:

for a same downlink transmitting beam, when less than and/or equal to 1,or Y, or Y/x, or X, or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐uplink beams among the actually used Y uplink beams are changed comparedto the X actually used uplink transmitting beams in the previous randomaccess attempt, the preamble power ramping counter is increased by 1;otherwise, the preamble power ramping counter remains unchanged;

in a case where one preamble power ramping counter is determined foreach preamble determined to be transmitted, the method for determiningthe counting result of the preamble power ramping counter includes:

when the uplink transmitting beam for transmitting the preamble ischanged, the preamble power ramping counter remains unchanged;otherwise, the preamble power ramping counter is increased by 1;

in a case where one preamble power ramping counter is determined for allpreambles determined to be transmitted, the method for determining thecounting result of the preamble power ramping counter includes:

during a new random access attempt, when less than and/or equal to 1, orY, or Y/x, or X, or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐ uplinkbeams among all the actually used Y uplink beams are changed compared toall the X actually used uplink transmitting beams in the previous randomaccess attempt, the preamble power ramping counter is increased by 1;otherwise, the preamble power ramping counter remains unchanged;

where the M, N, X and Y are all positive integers, and the x is a setratio.

The method further includes the step of:

during the transmission of the multiple preambles corresponding to eachof the determined downlink transmitting beams, calculating thetransmitting power by using a Path Loss (PL) obtained by a samecorresponding downlink transmitting beam; or,

calculating the transmitting power based on a unified PL.

The step of calculating the transmitting power based on a unified PLincludes:

selecting the PL corresponding to the downlink transmitting beam havingthe maximum Reference Signal Received Power (RSRP); or,

selecting the PL corresponding to the downlink transmitting beam havingthe minimum RSRP; or,

selecting an average of PLs corresponding to all downlink transmittingbeams; or,

randomly selecting, according to a predefined or configured RSRPthreshold, the downlink transmitting beam having a PL not greater thanor not less than the threshold with equal probability, and calculatingthe transmitting power by using the PL of the downlink transmittingbeam.

The method for determining the counting result of the preambletransmission counter includes:

whenever the UE performs a new random access attempt, increasing thepreamble transmission counter by 1; or,

whenever the UE performs a new random access attempt and there are Lpreambles determined to be transmitted in the new random access attempt,increasing the preamble transmission counter by L, where the L is apositive integer.

The method further includes the step of:

when the preamble transmission counter exceeds a preset preamble maximumpreamble_max, reporting a random access problem; or,

when the preamble transmission counter exceeds preamble_max*N*M,reporting a random access problem, where N is the number of thedetermined downlink transmitting beams, M is the number of preamblescorresponding to each of the downlink transmitting beams, and both M andN are positive integers.

The method further includes the step of:

starting a random access timer when the UE starts to transmit a firstpreamble, and reporting a random access problem when the random accesstimer expires; or,

reporting a random access problem when the preamble transmission counterexceeds the preset preamble maximum preamble_max or preamble_max*N*M andwhen the random access timer does not expire; or,

reporting a random access problem when the preamble transmission counterdoes not exceed the preset preamble maximum preamble_max orpreamble_max*N*M and when the random access timer expires;

where N is the number of the determined downlink transmitting beams, Mis the number of preambles corresponding to each of the downlinktransmitting beams, and both M and N are positive integers; and, thereporting a random access problem is reporting a random access problemto a higher layer.

The step of performing multiple preambles based random access includes:

determining a Random Access Response (RAR);

the method for determining the RAR includes:

detecting a matched RAR; or

detecting an RAR, continuously searching within a configured RAR searchwindow, and determining the RAR in the following way if multiple matchedRARs are found:

randomly selecting an RAR with equal probability;

selecting, according to an uplink grant, an RAR supporting the earliestsubsequent uplink transmission; and

determining an RAR according to a Hybrid Automatic Repeat reQuest (HARQ)progress ID indicated in the RAR.

The step of determining an RAR according to an HARQ progress IDindicated in the RAR includes:

if there are multiple different HARQ progress IDs, transmittingcorresponding uplink data according to an uplink grant indicated in thecorresponding RAR; or,

for a same HARQ progress ID, randomly selecting an RAR with equalprobability, or selecting, according to an uplink grant, an RARsupporting the earliest subsequent uplink transmission.

The step of determining, by a User Equipment (UE), random accessresources includes:

acquiring, by the UE, measurement reference signals configured by a basestation, the measurement reference signals including synchronizationsignal blocks and/or Channel State Information-Reference Signals(CSI-RSs); and

measuring, by the UE, the configured measurement reference signals toobtain a measurement result of the measurement reference signals,reporting the measurement result, and acquiring random access resourcesconfigured according to the measurement result by the base station.

The step of reporting the measurement result includes any one of thefollowing:

feeding back measurement results of all the configured measurementreference signals to the base station;

feeding back, according to a predefined or configured threshold and tothe base station, measurement results of all measurement referencesignals greater than or not less than the threshold; and

feeding back measurement results of all the configured measurementreference signals to the base station, and feeding back, according to apredefined or configured threshold and to the base station, indexes ofall measurement reference signals greater than or not less than thethreshold.

The step of determining, by a UE, random access resources includes:

reading, by the UE and from random access configuration informationtransmitted in a downlink channel by a base station, available randomaccess resources in the present cell; and

selecting, according to the measurement result of the measurementreference signals, indexes of the measurement reference signals toobtain corresponding random access resources.

The step of selecting, according to the measurement result of themeasurement reference signals, indexes of the measurement referencesignals includes:

selecting indexes of multiple measurement reference signals having theoptimal measurement result;

selecting, based on a preset or configured threshold, indexes of allmeasurement reference signals having a measurement result satisfying thethreshold; and

selecting, based on a preset or configured threshold, indexes ofmultiple measurement reference signals among all measurement referencesignals having a measurement result satisfying the threshold.

The method further includes the step of:

attempting to receive a signal on a channel, on which signals are to betransmitted, within a period of time before the real transmission ofsignals, indicating that this channel has been occupied if the receivedsignal energy is not less than a preset or configured threshold, andgiving up this transmission.

The present disclosure further provides a random access method,including steps of:

configuring, by a base station, random access resources; and

transmitting the random access resources, the random access resourcesbeing used for performing multiple preambles based random access by aUser Equipment (UE).

The present disclosure provides a user equipment, including:

an acquisition unit configured to determine random access resources; and

a random access unit configured to, when it is determined according tothe random access resources that multiple preambles based random accessis performed, determine a preamble sequence and an uplink transmittingbeam for transmitting multiple preambles, and perform multiple preamblesbased random access.

The present disclosure provides a base station, including:

a configuration unit configured to configure random access resources;and

a transmission unit configured to transmit the random access resources,the random access resources being used for performing multiple preamblesbased random access by a User Equipment (UE).

In conclusion, in the present disclosure, a User Equipment (UE)determines random access resources; and, when it is determined accordingto the random access resources that multiple preambles based randomaccess is performed, the maximum number of preambles that may betransmitted in one random access attempt and the preamble sequences anddownlink transmitting beams for the preambles that may be transmittedare determined according to the determined number of downlinktransmitting beams and the number of preambles that may be transmittedfor each downlink transmitting beam, and the multiple preambles basedrandom access is then performed. In the present disclosure, the apreamble pence and the uplink transmitting beam for transmittingmultiple preambles may be determined, so that the present disclosure mayrealize the random access to multiple preambles.

Additional aspects and advantages of the present disclosure will bepartially appreciated and become apparent from the descriptions below,or will be well learned from the practices of the present disclosure.

The purpose of the present invention is that the beam failure recoveryprocedure in the prior art is based on contention-free but does notsolve the problem of allocating contention-free time-frequency resourcesand sequence resources for different terminals with lower signalingoverhead. In addition, both the beam failure recovery procedure and theon demand system information transmitting request procedure are based onthe random access procedure, but the procedure optimization is notperformed on these two application scenarios. The present inventionoptimizes the above scenarios in order to reduce the delay of these twoscenarios.

In order to achieve the above objectives, the present invention providesa method for beam failure recovery request, comprising the followingsteps:

acquiring, by a terminal, channel time-frequency resource configurationinformation and preamble configuration information used for transmittinga beam failure recovery request;

selecting, by the terminal, a candidate downlink transmit beam accordingto a measurement result;

selecting, by the terminal, a channel time-frequency resource and/or apreamble according to association between a downlink transmit beam andthe channel time-frequency resource and/or the preamble, thetime-frequency resource configuration information and the preambleallocation information; and

transmitting, by the terminal, the preamble on the channeltime-frequency resource.

Preferably, the step of acquiring, by a terminal, configurationinformation such as channel time-frequency resource configurationinformation and preamble configuration information used for transmittinga beam failure recovery request comprises: acquiring, by the terminal,the configuration information such as the channel time-frequencyresource configuration information and the preamble configurationinformation used for transmitting the beam failure recovery request froma downlink control channel or a high layer signaling configuration.

Preferably, the preamble configuration information comprises a preamblegroup indication and an index indication within group.

Preferably, the preamble configuration information comprises a preamblestart index and a preamble number indication.

Preferably, the preamble group indication is used for indicating thenumber of preamble groups, and the index indication within group is usedfor indicating a preamble index within a group, allocated to theterminal, in the preamble group.

Preferably, the preamble group indication is used for indicating aninterval between adjacent preambles in a group, and the index indicationwithin group is used for indicating a preamble index within a group,allocated to the terminal, in the preamble group.

Preferably, the channel time-frequency resource configurationinformation comprises a channel indication index and a downlink beamindex.

Preferably, the channel time-frequency resource configurationinformation further comprises an available subframe index and/or anavailable radio frame index and a frequency offset indication.

Preferably, the measurement result is a reference signal receiving powerof the downlink signal, wherein, the downlink signal comprises: asynchronization signal block, a channel state information referencesignal (CSI-RS) and a beam reference signal.

Preferably, the terminal selects a time-frequency resource and apreamble corresponding to the candidate downlink transmit beam,according to the correspondence, the time-frequency resourceconfiguration information and the preamble configuration information.

Preferably, the method falls back to a contention-based random accessprocedure, if the downlink beam obtained by the terminal according tothe downlink measurement result does not exist in the correspondence orthe times of beam failure recovery request re-attempt of the terminalexceeds a pre-defined maximum attempt times.

Preferably, a terminal identification and the beam failure recoveryrequest indication are carried in message 3 of the contention-basedrandom access procedure.

Preferably, candidate downlink beam index information is further carriedin message 3.

Preferably, the candidate downlink beam index corresponds to one or moredownlink transmit beams, and one or more downlink beam index informationis transmitted in message 3.

Preferably, a beam failure recovery request response is carried inmessage 4 of the contention-based random access procedure.

The present invention provides a method for requesting to transmitsystem information, comprising the following steps of:

selecting, by a terminal, a preamble according to association between ondemand system information or system information group and a randomaccess preamble;

transmitting, by the terminal, the preamble in a random access channel;and

detecting, by the terminal, a random access response to acquire thetime-frequency resource location of the system information or systeminformation group.

Preferably, the correspondence between the system information or thesystem information group and the random access preamble is configured bya high layer signaling or a predetermined manner.

Preferably, the step of detecting, by the terminal, a random accessresponse to acquire the time-frequency resource location of the systeminformation or system information group comprises: acquiring thetime-frequency resource location of the system information or systeminformation group according to the downlink resource allocationinformation in the random access response, if a downlink control channelis scrambled by an Random Access-Radio Network Temporary Identity(RA-RNTI) corresponding to the random access channel, and the randomaccess response in a downlink shared channel indicated by the downlinkcontrol channel includes a preamble identifier matching the transmittedpreamble; or

acquiring, by the terminal, the time-frequency resource location of thesystem information/system information group according to the downlinkresource allocation information indicated in the downlink controlchannel, if the downlink control channel is scrambled by an on demandsystem information RNTI and the system information/system informationgroup indicated by the on demand system information RNTI includes thesystem information/system information group requested by the terminal.

The present invention provides a method for requesting to transmitsystem information, comprising the following steps of:

transmitting, by a terminal, a preamble: on a random access channel;

detecting, by the terminal, a random access response;

transmitting, by the terminal, message 3 on an uplink time-frequencyresource indicated by an uplink grant in the random access response,wherein, message 3 comprises a system information index; and

detecting, by the terminal, message 4 to acquire a time-frequencyresource location of system information/system information group.

Preferably, message 3 comprises a transmit beam indication.

Preferably, the transmit beam indication is a previous transmit beamindication which indicates a downlink transmit beam used for previouslytransmitting downlink data by the terminal; or

the transmit beam indication is at least one of a synchronization signalblock index, a channel state information reference signal index, a beamreference signal index, a beam index, and a beam direction deviationindication.

Preferably, the step of detecting, by the terminal, message 4 comprises:detecting, by the terminal, downlink control information in a downlinkcontrol channel, and allocating, by the terminal, message 4 according tothe downlink time-frequency resource allocation information, andacquiring the system information according to the downlinktime-frequency resource scheduling information in the message 4, if thedownlink control information is scrambled by a C-RNTI of the terminal ora temporary C-RNTI allocated by a base station.

Preferably, the step of detecting, by the terminal, message 4 comprises:detecting, by the terminal, downlink control information in a downlinkcontrol channel, and acquiring the system information according to thedownlink time-frequency resource allocation information in a controlinformation, if the downlink control information is scrambled by an ondemand system information RNTI and the system information and systeminformation group corresponding to the on demand system information RNTIcontains the system information and system information group requestedby the terminal.

The present invention provides an apparatus for beam failure recoveryrequest, comprising the following modules:

a configuration information acquisition module, configured to acquirechannel time-frequency resource configuration information and preambleconfiguration information for transmitting a beam failure recoveryrequest;

a candidate downlink transmit beam selecting module, configured toselect a candidate downlink transmit beam according to a measurementresult;

a channel time-frequency resource and preamble selecting module,configured to select a channel time-frequency resource and/or apreamble, according to the correspondence between the downlink transmitbeam and the channel time-frequency resource and/or the preamble, andthe channel time-frequency resource configuration information and thepreamble configuration information; and

a preamble transmitting module, configured to transmit the selectedpreamble on the selected channel time-frequency resource.

The present invention provides an apparatus for requesting to transmitsystem information, comprising the following modules:

a preamble selecting module, configured to select a preamble accordingto association between on demand system information or systeminformation group and a random access preamble;

a preamble transmitting module, configured to transmit the preamble on arandom access channel; and

a random access response detecting module, configured to detect a randomaccess response and acquire a time-frequency resource location of thesystem information or system information group.

The present invention provides an apparatus for requesting to transmitsystem information, comprising the following modules:

a preamble transmitting module, configured to transmit a preamble on arandom access channel;

a random access response detecting module, configured to detect a randomaccess response;

a message 3 transmitting module, configured to transmit message 3according to are uplink grant indication in the random access response,wherein message 3 comprises a system information index; and

a message 4 detecting module, configured to detect a message 4 andacquire a time-frequency resource location of the system information andsystem information group.

Compared with the prior art, the technical effects of the presentinvention include, but are not limited to: the signaling overhead usedfor configuring the time-frequency resources and the preamble for thecontention-free beam failure recovery procedure can be reduced, and thedelay of the beam failure recovery can be reduced by optimizing the beamfailure recovery request response and falling back to thecontention-based random access procedure; by optimizing the randomaccess response, the structure of message 3, and the structure ofmessage 4, the request delay for on demand system information can alsobe reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to illustrate the technical solution of the embodiment of thepresent invention more clearly, the accompanying drawings used in thedescriptions of embodiments will be introduce briefly. Obviously, theaccompanying drawings in the following description are only someembodiments of the present invention, and other drawings can be obtainedaccording to the following drawings on the premise that without anycreative labor is paid out for those skilled in the art.

FIG. 1 is a schematic flowchart of a conventional contention-basedrandom access;

FIG. 2 is a schematic flowchart of a method for generating a preambleaccording to an embodiment of the present invention;

FIG. 3 is an example 1 of configuring a preamble for a beam failurerecovery request;

FIG. 4 is an example 2 of configuring a preamble for a beam failurerecovery request;

FIG. 5 is an example 3 of configuring a preamble for a beam failurerecovery request;

FIG. 6 is an example 4 of configuring a preamble for a beam failurerecovery request;

FIG. 7 is an example 5 of configuring a preamble for a beam failurerecovery request;

FIG. 8 is an example 6 of configuring a preamble for a beam failurerecovery request;

FIG. 9 is a schematic diagram of a User Equipment (UE) according to thepresent invention;

FIG. 10 is a schematic diagram of a base station equipment according tothe present invention.

FIG. 11 is a schematic flowchart of a random access method according toan embodiment of the present disclosure;

FIG. 12 is an exemplary diagram of an association betweensynchronization signal blocks and random access occasions according toan embodiment of the present disclosure;

FIG. 13 is an exemplary diagram of an association betweensynchronization signal blocks and random access occasions according toan embodiment of the present disclosure;

FIG. 14 is an exemplary diagram of a preamble indication manneraccording to an embodiment of the present disclosure; and

FIG. 15 is a schematic flowchart of a random access method according toan embodiment of the present disclosure.

FIG. 16 is a schematic flowchart of a conventional contention-basedrandom access;

FIG. 17 is a first exemplary diagram of a random access resourceconfiguration based on multiple preambles;

FIG. 18 is a second exemplary diagram of a random access resourceconfiguration based on multiple preambles;

FIG. 19 is a third exemplary diagram of a random access resourceconfiguration based on multiple preambles;

FIG. 20 is an exemplary diagram of the number of actually transmittedpreambles;

FIG. 21 is a first exemplary diagram of a transmission of multiplepreambles based on unlicensed spectra;

FIG. 22 is a second exemplary diagram of a transmission of multiplepreambles based on unlicensed spectra;

FIG. 23 is a third exemplary diagram of a transmission of multiplepreambles based on unlicensed spectra;

FIG. 24 is a schematic flowchart of an embodiment of a random accessmethod according to the present disclosure; and

FIG. 25 is a schematic structure diagram of an embodiment of a userequipment according to the present disclosure.

FIG. 26 is a flowchart of a beam failure recovery;

FIG. 27 is a flowchart of a beam failure recovery request according tothe present invention;

FIG. 28 is an allocation manner for preambles;

FIG. 29 is a possible preamble configuration format;

FIG. 30 is another configuration manner for preambles;

FIG. 31 is an indication manner for preambles;

FIG. 32 is an apparatus for a beam failure recovery request according tothe present invention;

FIG. 33 is an apparatus for requesting on demand system informationaccording to the present invention; and

FIG. 34 is another apparatus for requesting on demand system informationaccording to the present invention.

DETAILED DESCRIPTION

To make those skilled in the art understand the technical solutions ofthe specific implementation better, the technical solutions in theembodiments of the specific implementation will be clearly andcompletely described below with reference to the accompanying drawingsin the embodiments of the specific implementation.

In some flows described in the specification and the claims of thisimplementation and in the accompanying drawings, there are multipleoperations which occur in a specific order. However, it should beclearly understood that these operations may be performed without theorder in which they occur in the article or may not be performed inparallel. The numbers for operations such as 101, 102 are just providedto distinguish different operations and the numbers themselves do notrepresent any execution order. In addition, these flows may include moreor less operations and these operations may be performed in order orperformed in parallel. It is to be noted that, the description such as“the first” and “the second” in the article is used to distinguishdifferent messages, devices and modules. It does not represent any orderand does not define that “the first” and “the second” are differenttypes.

The technical solutions in the embodiments of the specificimplementation will be clearly and completely described below withreference to the accompanying drawings in the embodiments of thespecific implementation. Apparently, the embodiments described hereinare merely a part but not all of the embodiments of the specificimplementation. All other embodiments obtained by those skilled in theart without paying any creative effort on the basis of the embodimentsin the specific implementation are within the protection scope of thespecific implementation.

The present invention provides a method for configuring information, asshown in FIG. 2. Dedicated beam failure recovery resources (includingresources such as preamble resources and time-frequency resources) areconfigured for a UE to perform a beam failure recovery, wherein thepreamble resources include a dedicated cyclic shift indication, a rootsequence indication, etc. The present invention also provides how the UEacquire the preamble resources for a beam failure recovery by acquiredconfiguration information of random access preamble resources(contention-based and contention-free random access preamble resources)and dedicated beam failure recovery resource information.

From the network device side, a gNB will configure preamble resourcesfor a random access in system information, including root sequenceindices, cyclic shifts and number of available random access preambles(wherein the total number of available preambles and/or the number ofpreambles for a contention-based random access and/or the number ofpreambles for a contention-free random access can be included).

A base station will also configure preamble resources for a beam failurerecovery request used by the UE, including one or more of the following:root sequence index, cyclic shift value and preamble index, wherein:

1. The root sequence index indicates a basic root sequence used forgenerating UE-dedicated preamble resources; the root sequence index maybe a physical root sequence index, or a logic root sequence index. Theroot sequence index for the beam failure recovery request may be:

a) obtained according to the root sequence index in the random accesspreamble configuration, for example, the root sequence index indicatingthe beam failure recovery request may be equal to the root sequenceindex of random access preamble, or a relative offset may be set;

b) configured separately.

2. The cyclic shift value indicate the size of the shift on the rootsequences, by which the UE determines the shift between every twoadjacent preambles. The cyclic shift value for the beam failure recoveryrequest may be:

a) confirmed according to the cyclic shift value in the random accesspreamble configuration, for example, the cyclic shift value indicatingthe beam failure recovery request may be equal to the cyclic shift valueof the random access preamble, or it is scaled down or scaled up, or arelative offset is set;

b) configured separately.

3. The preamble index indicates how many cyclic shifts occurred when theroot sequence of the UE is produced. The preamble index for the beamfailure recovery request may be:

a) contention-free random access preamble index configuration which isconfigured according to the random access preamble, for example, it maybe informed that the preamble index for the beam failure recoveryrequest is the same as the random access preamble index, or a relativeoffset is set;

b) configured separately, the details of which will be described below.

i. the preamble index may be determined according to the number ofpreambles to be supported by the beam failure recovery request, forexample, the number of preambles to be supported by the beam failurerecovery request is N and the preamble index are directly given a valuefrom 0 to N−1.

ii. the preamble index may be determined according to the number ofpreambles to be supported by the beam failure recovery request withinthe cyclic shift value of every contention-free preamble. For example,within one cyclic shift value, the gNB also supports M preambles for thebeam failure recovery request. Therefore, the preamble index here isindicated to be given a value from 0 to M−1, and preambles for the beamfailure recovery request, which are determined finally, are collectivelyconfirmed according to random access preamble configuration informationand preamble configuration information for the beam failure recoveryrequest.

From the UE side, the UE will read the system information to acquirepreamble resource configuration information for a random access which istransmitted by a system in the initial access or link state. Inaddition, the UE will also receive preamble resources for the beamfailure recovery request from the gNB, which is acquired by a downlinkchannel, and determine its own preamble sequence for the beam failurerecovery request, wherein:

1. The preamble sequence configured for the UE is found directlyaccording to a root sequence indicated by the root sequence index andthe configured cyclic shift value and preamble index.

a) it is to be noted that, if the beam failure recovery request andrandom access request share time-frequency resources while they aredistinguished from preamble resources, that is, CDM, when the gNB isconfiguring the preamble index, it should avoid collision with preamblesfor random access, for example, a part of or all of contention-freerandom access preamble resources in a contention-free random accesspreamble resource pool are configured for the beam failure recoveryrequest.

2. The UE can find the starting point of contention-free preambleaccording to the root sequence indicated by the root sequence index, thecyclic shift value configured for the random access, the number ofcontention-based preambles and the number of preambles supported bycorresponding Synchronization Signal blocks (SS blocks) or Random AccessChannel occasion (RACH occasion), and find the preamble sequencesconfigured for the UE according to the cyclic shift value and preambleindex configured by a BFRQ. Particularly

a) the UE is informed of a contention-free preamble index, and by usingthe contention-free preamble index as the starting point, the UE findsthe preamble sequence configured for itself according to the cyclicshift value and the preamble index configured by the BFRQ.

In one embodiment, a method for configuring information according to thepresent invention will be introduced. A gNB configures preamble resourceinformation for a beam failure recovery request and informs the UE ofthe information. After the UE acquires the configuration information,the preamble sequence for a beam failure recovery request of a user isdetermined finally by preamble configuration information for a beamfailure recovery request and random access preamble configurationinformation which may be used.

From the network device side, a gNB will configure preamble resourcesfor random access in system information, including root sequence index,cyclic shift value and number of available random access preambles(wherein the total number of available preambles and/or the number ofpreambles for contention-based random access and/or the number ofpreambles for contention-free random access may be included).

A base station will also configure dedicated UE-dedicated preambleresources for a beam failure recovery request, which may include one ormore of the following: root sequence index, cyclic shift value andpreamble index, wherein:

1. The root sequence index indicate a basic root sequence used forgenerating UE-dedicated preamble resources; the root sequence index maybe a physical root sequence index, or a logic root sequence index. Theroot sequence index for the beam failure recovery request may be:

a) obtained by the UE according to the root sequence index in the randomaccess preamble configuration, for example:

i. the root sequence index of the beam failure recovery request presetby a network may be equal to the root sequence index of the randomaccess preamble, that is, they are configured as:Root_sequence_BFRQ=Root_sequence_BFRQ_RA;

ii. the root sequence index for the beam failure recovery requestconfigured by the network may set an offset ΔRoot_sequence relative tothe root sequence index of random access preamble, i.e.Root_sequence_BFRQ=Root_sequence_BFRQ_RA+ΔRoot_sequence;

b) configured separately, that is, they are configured as specificvalues. The values are selected from a root sequence resource pool ofthe random access preamble, i.e. Root_sequence_BFRQ=N_value. And takingLTE as an example, N_value is a value selected from 0-837.

2. The cyclic shift value indicate the size of the shift on the rootsequences, by which the UE determines the shift of every two adjacentpreambles. The cyclic shift value for the beam failure recovery requestinclude:

a) acquired by the UE according to the cyclic shift value (which isrepresented as CS_ra) in the random access preamble configuration, forexample, the cyclic shift value (which is represented as CS_bfrq) forthe beam failure recovery request may be:

i. equal to the cyclic shift value of the random access preamble whichis preset by the network, i.e. CS_bfrq=CS_ra.

ii. changed on the scale by the UE according to the cyclic shift valueof the random access preamble, that is, a scale factor β is configuredon the network side, i.e. CS_bfrq=CS_ra*β. β may be a decimal between 0and 1, which indicates that CS_bfrq is scaled down according to acertain scale CS_ra. β may be greater than 1, which indicates thatCS_bfrq is scaled up according to a certain scale CS_ra. β may beinformed according to direct M bits or the true β value may be read froma pre-defined table according to M bits. As shown in the below table, 2bits are used to indicate 4 possible β values.

TABLE 1 Exemplary table indicating cyclic shift value scale Bit value βvalue 00 0.25 01 0.5 10 0.75 11 1

iii. acquired by the UE according to an offset ΔCS relative to thecyclic shift value of the random access preamble, that is, ΔCS isconfigured on the network side and configured as CS_bfrq=CS_ra+ΔCS. Theoffset ΔCS may be a negative number, which indicates decrease of thecyclic shift relative to CS_ra; the offset may be a positive number,which indicates increase of the cyclic shift value relative to CS_ra.The offsets ΔCS may be directly informed by M bits, that is, bit valuesrepresent specific offsets. And the true offsets may also be read from apre-defined table by M bits.

TABLE 2 Exemplary table indicating cyclic shift value offset Bit valueΔCS value 00 −8 01 −4 10 −2 11 0

b) the CS_bfrq is configured separately, that is, it is configured thatCS_bfrq=N_cs. The N_cs is selected from cyclic shift values availablefor the random access.

3. The preamble index indicates how many cyclic shifts occurred when theroot sequence of the UE is produced. The preamble index(preamble_index_bfrq) for the beam failure recovery request include:

a) configured by the UE according to a contention-free random accesspreamble index (preamble_index_ra) configured by the random accesspreamble, for example, the network may preset that the preamble indexfor the beam failure recovery request is the same as the preamble indexfor the random access, i.e. preamble_index_bfrq=preamble_index_ra; orconfigured by the UE according to a relative offset Δpreamble_indexconfigured by the network, i.e.preamble_index_bfrq=preamble_index_ra+Δpreamble_index; specifically,Δpreamble_index may be directly informed by M bits, or read from acorresponding table in the way similar to table 1 and table 2 which willnot be described again;

b) configured separately, the details of which will be described below.

i. the preamble index may be determined according to the number ofpreambles to be supported by the beam failure recovery request, forexample, the number of preambles to be supported by the beam failurerecovery request is N and the preamble indices are directly given avalue from 0 to N−1.

ii. the preamble index may be determined according to the number ofpreambles to be supported by the beam failure recovery request withinthe cyclic shift value of every contention-free preamble. For example,within one cyclic shift value, the gNB also supports M preambles for thebeam failure recovery request. Therefore, the preamble index here isindicated to be given a value from 0 to M−1, and the preamble for thebeam failure recovery request which is determined finally iscollectively confirmed according to random access preamble configurationinformation and preamble configuration information for the beam failurerecovery request.

After generating configuration information, the net device transmits theconfiguration information to the UE by a downlink channel (broadcastchannel, physical downlink control channel or physical downlink sharedchannel); then, the network device retrieves possible preamble sequencestransmitted by the UE on corresponding time-frequency resourcesaccording to the configured preamble information.

From the UE side, the UE will read the system information to acquirepreamble resource configuration information for a random access which istransmitted by a system in the initial access or link state. Inaddition, the UE will also receive preamble resources for the beamfailure recovery request from the gNB which are acquired through adownlink channel, and determine the preamble sequence for the beamfailure recovery request, including:

1. The preamble sequence allocated to the UE are found directlyaccording to root sequence indicated by the root sequence index, and theacquired cyclic shift value and preamble index.

For example, when the beam failure recovery request and random accessare distinguished in the frequency domain, the configured preamblesequence is determined completely on the given root sequence accordingto the cyclic shift value and the preamble index for the beam failurerecovery request. As shown in FIG. 3, the UE may determine the preamblesequence configured for itself on the network side from the startingpoint of the root sequence according to the cyclic shift value andpreamble index.

In addition, if the beam failure recovery request and the random accessrequest are share time-frequency resources while they are distinguishedfrom preamble resources, that is, CDM, when the gNB is configuring thepreamble index, it should avoid collision with preambles for the randomaccess, for example, a part of or all of contention-free random accesspreamble resources in a contention-free random access preamble resourcepool are configured for the beam failure recovery request. Wherein thereare three ways, which are as follows respectively:

a) the first way is shown in FIG. 4. The preamble index still startsfrom the initial, but the number of preambles which are actuallyavailable for being actually read by the UE is configured fromcontention-free random access preamble resources.

b) the second way is shown in FIG. 5. The preamble index for the beamfailure recovery starts directly from the starting position of thecontention-free random access preamble index. In this case, the UE firstneeds to find the starting position of the contention-free random accesspreamble index (preamble_index_CFRA) by the configuration of randomaccess preambles. Taking LTE as an example, there are 64 preambles intotal, where 0-31 preambles are configured as contention-based randomaccess preambles, 32-63 preambles are configured as contention-freerandom access preambles, then preamble_index_CFRA={32,33, . . . 63},that is, the starting position is 32. For the UE which needs to performbeam failure recovery scanning, the position of the 32nd preamble isfound first according to the cyclic shift value and preamble indexconfigured by the random access preamble. Then it is used as thestarting point, and the configured preamble sequence of the UE aredetermined according to preamble cyclic shift value and preamble index(preamble_index_bfrq) configured by beam failure recovery request.

A dedicated contention-free random access preamble index is configuredfor the UE simultaneously. The UE may determine the starting position ofthe preamble for the beam failure recovery request by the random accesspreamble configuration and the dedicated contention-free random accesspreamble index. Taking LTE as an example, there are 64 preambles intotal, where 0-31 preambles are configured as contention-based randomaccess preambles, 32-63 preambles are configured as contention-freerandom access preambles, then preamble_index_CFRA={32, 33, . . . 63} andan dedicated preamble_index_cfra=40 is configured for the UE, that is,the starting position of the preamble for the beam failure recoveryrequest is the random access preamble index 40. For the UE which needsto perform beam failure recovery scanning, the position of the 40thpreamble is found first according to the cyclic shift value and preambleindex configured by the random access preambles. Then it is used as thestarting point, and the configured preamble sequence of the UE aredetermined according to preamble cyclic shift value and preamble index(preamble_index_bfrq) configured by the beam failure recovery request,as shown in FIG. 6.

A dedicated contention-free random access preamble index is configuredfor the UE simultaneously. The UE may determine the starting position ofthe preamble for the beam failure recovery request by the random accesspreamble configuration and the dedicated contention-free random accesspreamble index. Taking LTE as an example, there are 64 preambles intotal, where 0-31 preambles are configured as contention-based randomaccess preambles, 32-63 preambles are configured as contention-freerandom access preambles, then preamble_index_CFRA={32, 33, . . . 63} andan dedicated preamble_index_cfra=40 is configured for the UE, that is,the starting position of the preamble for the beam failure recoveryrequest is the random access preamble index 40. For the UE which needsto perform beam failure recovery scanning, the position of the 40thpreamble is found first according to the cyclic shift value and preambleindex configured by the random access preambles. Then it is used as thestarting point, and the configured preamble sequence of the UE aredetermined according to preamble cyclic shift value and preamble index(preamble_index_bfrq) configured by the beam failure recovery request.In this case, particularly, only the random access preamble index 40 isused as the starting point of the preamble for the beam failure recoveryrequest and is determined within one random access preamble cyclicshift, that is, the random access preamble index 41 is not used for thebeam failure recovery request, as shown in FIG. 7.

c) the third way is that preamble configuration for the beam failurerecovery request acquired by the UE is the same as random accesspreamble configuration, and the UE acquires the dedicated preamble indexfor the beam failure recovery request to perform the beam failurerecovery request, as shown in FIG. 8.

The above ways according to the preset invention will not be limited toa beam failure recovery. For the objectives of on-demand systeminformation transmitting and the scheduling request, similar ways mayalso be used.

The present invention further provides a User Equipment (UE), as shownin FIG. 9, comprising the following modules:

a preamble resource configuration information acquisition module,configured to receive random access preamble configuration and dedicatedpreamble configuration information;

a dedicated preamble determination module, configured to determine rootsequence configuration information of a dedicated preamble, dedicatedcyclic shift value configuration information and dedicated preambleindex;

a dedicated preamble generation module, configured to generate thededicated preamble according to the determined root sequenceconfiguration information of the dedicated preamble, the determinedcyclic shift value configuration information and the determined preambleindex; and

a dedicated preamble transmitting module, configured to transmit thededicated preamble on dedicated time-frequency resources configured by abase station.

The present invention further provides a base station equipment, asshown in FIG. 10, comprising the following modules:

a configuration information transmitting module, configured to transmitrandom access preamble configuration information and dedicated preambleconfiguration information; and

a preamble detection module, configured to detect the dedicated preambleon the configured dedicated time-frequency resources.

In several embodiments according to the specific implementation, itshould be understood that the disclosed systems, devices and methods maybe implemented in other ways. For example, the device embodimentdescribed above is just exemplary. For example, the division of theunits is just a division of logic functions, and the actualimplementation may have addition division way, for example, multipleunits or components may be combined or may be integrated into anothersystem, or some features may be ignored or not be performed. Anotherpoint is that coupling with each other or direct coupling orcommunicative connection as shown or discussed here may be via someinterfaces, and indirect coupling or communicative connection betweendevices or units may be electrical, mechanical or in other forms.

The unit as a separator for illustration can be separated physically orcannot be separated physically, the unit as a display component can be aphysical unit or cannot be a physical unit, in other word, the displayunit can located in one place, or the physical unit can be distributedto a multiple of network units. Part of units or all the units can beselected according to the actual requirement to realize the purpose ofthe embodiment.

In addition, each functional unit in each embodiment of the specificimplementation can be integrated into a processing unit; or, each unitcan exist alone physically; or, two or more units can be integrated intoone unit. The integrated unit can be implemented in the form ofhardware, or can be implemented in the form of a software functionalunit.

All terms (including technical and scientific terms) used herein havethe same meaning as that commonly understood by one of ordinary skill inthe art unless otherwise defined herein.

It should be noted that the method provided by the embodiments isapplicable to a contention-based or contention-free random accessmethod.

Taking a 5G network as an example, for the preamble problem in a 5Gnetwork, an embodiment of the present disclosure provides a randomaccess method as shown in FIG. 11, and the method is performed by aterminal device having a wireless communication function.

In the method, the terminal device first obtains a maximum number ofpreambles.

Specifically, the system may obtain the maximum number of preamblesaccording to initial access configuration information or random accessconfiguration information. The random access configuration informationmay also include preamble configuration information, random accesschannel configuration information, and the like.

The initial access configuration information may include down-linksignal configuration information. The initial access configurationinformation may also include configuration information used for theinitial access procedure. Generally, it includes synchronization signalblock configuration information, random access configurationinformation, and the like. The down-link signal configurationinformation may be included in the synchronization signal blockconfiguration information. The random access configuration informationis used to configure the random access procedure, and includes randomaccess channel configuration information and preamble configurationinformation, and the like.

Specifically, the maximum number of preambles may be determinedaccording to pre-defined system information and an association betweenthe pre-defined system information and the maximum number of preambles.The pre-defined system information may include but is not limited to anyof the following: preamble format; sub-carrier spacing of random accesschannel; the repetition number of sequences within one preamble; amaximum value of a plurality of numbers of down-link signals associatedto a same random access occasion; and a number of down-link signalsassociated to a currently selected random access occasion.

After obtaining the maximum number of preambles, the terminal devicegenerates a random access preamble according to the maximum number ofpreambles and preamble configuration information.

The preamble configuration information may include root sequenceconfiguration information, cyclic shift configuration information, andthe like. Specifically, the system may generate the random accesspreamble according to the maximum number of preambles and the rootsequence configuration information, the cyclic shift configurationinformation.

Subsequently, the terminal device transmits the generated random accesspreamble on a random access channel.

Specifically, in an embodiment of the present disclosure, a randomaccess method will be described in conjunction with a specific system.In the random access method of this embodiment, the number of preamblesis indicated and configured in an explicit manner.

In this embodiment, the system indicates the random access configurationinformation using Remaining Minimum System Information (RMSI). Thesystem herein may include various terminal devices having a wirelesscommunication function.

The system supports a plurality of the maximum numbers of preambles. Forexample, in addition to the number of preambles 64 supporting LTE, thesystem also supports more numbers of preambles, such as 128 and 256 andso on. To support a plurality of possible maximum numbers of preambles,new indication or configuration information may be added to RMSI orother system information OSI for supporting a plurality of possiblemaximum numbers of preambles. Specifically, the maximum number ofpreambles may be configured by using an index table. A possible indextable is shown in Table 3.

TABLE 3 Configuration of maximum number of preambles Index Maximumnumber of preambles 0 64 1 128 2 256 . . . . . .

In the remaining minimum system information RMSI or the other systeminformation OSI, a parameter for characterizing the maximum number ofpreambles is added, and indication and configuration are performed in anindex manner. The parameter may be separately notified. In this case,the random access configuration information in the RMSI or OSI includes:random access preamble configuration information, random access channelconfiguration information, and the configuration information of themaximum number of preambles. Alternatively, the parameter may also bepart of the random access preamble configuration information. In thiscase, the random access configuration information in the RMSI or OSIincludes: random access preamble configuration information (includingroot sequence configuration information, cyclic shift configurationinformation and the configuration information of the maximum number ofpreambles), random access channel configuration information, and thelike.

The terminal device reads the random access configuration information inthe RMSI or OSI when it is performing the initial access. It determinesthe number of available preambles based on the configuration informationof the maximum number of preambles therein, generates a preambleaccording to the root sequence configuration information and the cyclicshift configuration information in the random access preambleconfiguration information, and transmits the preamble on a random accesschannel.

After transmitting the random access preamble, the terminal devicedetects the random access response transmitted by the base station, anddetermines the random access preamble according to the preambleidentifier in the random access response.

Specifically, the terminal device determines the preamble identifier inthe random access response according to a predetermined indicationmanner of the preamble identifier; and determines the random accesspreamble according to the preamble identifier. The indication manner ofthe preamble identifier will be described in detail in the subsequentsections.

In another embodiment of the present disclosure, another method ofproviding a preamble will be described in connection with a specificsystem. In this embodiment, the number of preambles is indicated andconfigured in an implicit manner.

In this embodiment, the maximum number of preambles is indicated andconfigured by establishing an association between the preamble formatand the maximum number of preambles. Specifically, the maximum number ofpreambles available to the terminal device is implicitly indicated bydefining the maximum number of preambles associated to each preambleformat. The connection between the preamble format and the maximumnumber of preambles may be established by means of pre-defining. Forexample, a possible implementation is to add a parameter forcharacterizing the maximum number of preambles in the preamble formattable. As an example, a possible preamble format table is shown in Table4:

TABLE 4 Preamble format table for notifying the maximum number ofpreambles Preamble Preamble Configuration of format configurationmaximum number index information of preambles 0 Configuration 0 64 1Configuration 1 64 2 Configuration 2 128 3 Configuration 3 128 . . . . .. . . .

In Table 4, two configurations of the maximum number of preambles areused, that is, 64 and 128, respectively. The parameters used tocharacterize the preamble configuration information in the table includethe sequence length, the repetition number of sequences within onepreamble, the length of cyclic prefix, and the like. Configurationinformation such as sub-carrier spacing of preamble may also beincluded.

In this implementation, the preamble format s configured by means ofindexing and notified in the random access configuration information.

When performing initial access, the terminal device reads the randomaccess preamble format from, for example, RMSI or OSI, determines theavailable maximum number of preambles according to the configurationinformation of the maximum number of preambles in the preamble format,and generates an associated preamble according to the root sequenceconfiguration information and the cyclic shift configurationinformation.

In addition to determining the configuration information of the maximumnumber of preambles according to the preamble format, the configurationinformation of the maximum number of preambles may also be implicitlynotified according to other parameter(s) for determining the preamble.For example, the maximum number of preambles is determined according tothe sub-carrier spacing used for the random access channel or thepreamble. That is, the association between the sub-carrier spacing ofrandom access channel and the maximum number of preambles isestablished, and the maximum number of preambles is implicitly notifiedand configured by configuring the sub-carrier spacing of random accesschannel.

For example, a possible way is to pre-define the association between thesub-carrier spacing of random access channel and the maximum number ofpreambles. For example, the association is established by way of anindex table. As an example, a possible index table is shown in Table 5.

TABLE 5 Association between sub-carrier spacing and maximum number ofpreambles Sub-carrier spacing (kHz) Maximum number of preambles 15 64 3064 60 128 120 128

In Table 5, different maximum numbers of preambles are defined fordifferent sub-carrier spacings. The maximum number of preambles isimplicitly notified by the configuration of the sub-carrier spacing ofrandom access channel. Specifically, the sub-carrier spacingconfiguration parameter may be notified in the preamble format, that is,it may be configured with the preamble format as part of the preambleformat. In this case, the terminal device determines the maximum valueof the number of preambles according to the sub-carrier spacing in thepreamble format. In an alternative manner, the sub-carrier spacing maybe separately notified. The terminal device determines the sub-carrierspacing of the random access channel according to the sub-carrierspacing configuration information in the random access configurationinformation, determines the associated maximum number of preambles atthe same time, and generates a preamble according to the root sequenceconfiguration information and the cyclic shift configuration informationin the preamble configuration information.

In an alternative implementation, the association between the repetitionnumber of sequences within one preamble and the maximum number ofpreambles may also be established to implicitly notify the maximumnumber of preambles. For example, the association between the repetitionnumber of sequences within one preamble and the maximum number ofpreambles is established by means of pre-defining. As an example, apossible way is shown in Table 6.

TABLE 6 Association between the repetition number of sequences withinone preamble and the maximum number of preambles Repetition number ofsequences Maximum number within one preamble of preambles 1 64 2 64 4 646 128 12 128 . . . . . .

The repetition number of sequences within one preamble may betransmitted in the preamble format, and may also be directly included inthe random access configuration information as a parameter. Uponreceiving the preamble format or the random access configurationinformation including the parameter in the RMSI or OSI, the terminaldevice determines the maximum number of preambles according to therepetition number of sequences within one preamble, and generates anassociated preamble according to the root sequence configurationinformation and the cyclic shift configuration information or the likein the preamble configuration information.

In another embodiment of the present disclosure, another random accessmethod will be described in conjunction with a specific system. In therandom access method of this embodiment, the number of preambles isnotified and configured in an implicit manner.

In this embodiment, the maximum number of preambles is implicitlynotified by establishing the association between the number of down-linksignals mapped to the same random access occasion and the maximum numberof preambles. The down-link signal may be a synchronous signal block ora channel state information reference signal, etc. The followingdescription is provided by taking the synchronous signal block as anexample. For systems operating at high frequency bands, beam-formingtechniques are required to traverse severe path losses in high frequencybands wireless communication environments. Therefore, beam pairing atthe transmitter and receiver is very important. For the initial accessprocedure at high frequency bands, in addition to establishing theinitial up-link and down-link synchronization, it is also necessary toobtain the initial beam pairing. The existing manner in which the basestation acquires the direction of the down-link transmit beam is that:an association is established between the down-link synchronizationsignal block (or down-link signal) and the random access occasion andthe preamble set, and the direction of the down-link beam that transmitsthe random access response is obtained by the detection of the randomaccess preamble. This procedure may be described in FIG. 12.

FIG. 12 is a schematic diagram illustrating a one-to-one associationbetween synchronization signal blocks and random access occasions. Thatis, there is merely one synchronization signal block mapped to eachrandom access occasion, and the base station may determine thesynchronization signal block according to the random access occasion atwhich the transmitted preamble was detected so as to know the beamdirection in which the random access response is transmitted.

For some up-link and down-link allocations in time divisionmultiplexing, there are more synchronization signal blocks, and fewerrandom access occasions are available. In this case, there may bemultiple synchronization signal blocks mapped to the same random accessoccasion, and the base station needs to know the synchronization signalblock information by means of grouping the preamble so as to obtain thebeam direction in which the random access response is transmitted.

A simple example is as follows. The maximum number of preamblessupported by the system is 64, and since the up-link time-frequencyresources are more limited, there are fewer random access occasions. Atthe same time, because there are more beams, more down-linksynchronization signal blocks are needed, so two synchronization signalblocks correspond to one random access occasion. In this case, althoughthe number of preambles available at each random access occasion is 64,in order to distinguish the synchronization signal blocks mapped to thesame random access occasion, the available preambles need to be dividedinto two non-overlapping sets. Each set includes 32 preambles and isused to indicating one synchronization signal block associated to therandom access occasion, respectively. The above configuration may bebriefly described with FIG. 13.

FIG. 13 depicts an example schematic diagram of the association betweensynchronization signal blocks and random access occasions. As can beseen from FIG. 13, when a plurality of synchronization signal blocks aremapped to the same random access occasion, the preambles available tothe terminal device will be reduced, thereby increasing the collisionprobability and reducing the initial access performance. Therefore, themaximum number of available preambles may be increased when a pluralityof synchronization signal blocks are mapped to the same random accessoccasion, thereby reducing the collision probability and improving theinitial access performance. Still taking the foregoing example as anexample, if the maximum number of preambles is increased to 128, thenumber of preambles in the preamble set associated to eachsynchronization signal block is 64. The collision probability and theaccess performance are both the same as the case where there is aone-to-one association between the synchronization signal blocks and therandom access occasions.

A possible way to determine the maximum number of preambles is toestablish an association between the number of down-link synchronizationsignal blocks associated to the same random access occasion and themaximum number of preambles, and implicitly configure and notify themaximum number of preambles according to the number of down-linksynchronization signal blocks associated to the same random accessoccasion. The association between the number of down-linksynchronization signal blocks associated to the same random accessoccasion and the maximum number of preambles may be established in apredefined manner. A simple example is shown in Table 7.

TABLE 7 Association between the number of down-link synchronizationsignal blocks associated to the same random access occasion and themaximum number of preambles Number of down-link synchronization signalblocks associated to the Maximum number same random access occasion ofpreambles 1 64 2 64 4 128 8 128 . . . . . .

Another possible notification and configuration approach is to set thefollowing criteria. If the number of down-link synchronization signalblocks associated to the same random access occasion is greater than orequal to a pre-defined threshold, the maximum number of preambles 128 isto be used; otherwise the maximum number of preambles 64 is to be used.For the case of configuring more possible maximum numbers of preambles,a plurality of thresholds are defined, and the maximum number ofpreambles is determined according to the comparison with the thresholds.Specifically, for the K maximum numbers of preambles, K−1 thresholds aredefined, and the maximum number of preambles is selected according tothe following criteria:

If the number of down-link synchronization signal blocks associated tothe same random access occasion<threshold 0, the 0th maximum number ofpreambles is selected;

If threshold 0≤the number of down-link synchronization signal blocksassociated to the same random access occasion<threshold 1, the firstmaximum number of preambles is selected;

If threshold 1≤the number of down-link synchronization signal blocksassociated to the same random access occasion<threshold 2, the secondmaximum number of preambles is selected;

. . .

If threshold K−1≤the number of down-link synchronization signal blocksassociated to the same random access occasion, the K-th maximum numberof preambles is selected.

Taking the case of 4 maximum numbers of preambles as an example, theselection and configuration manner of the maximum number of preamblesare briefly described. The 4 maximum numbers of preambles are 64, 128,256, and 512, respectively. First the thresholds 4, 16, 32 are defined,and the maximum number of preambles is selected according to thefollowing criteria:

If the number of down-link synchronization signal blocks associated tothe same random access occasion<4, the maximum number of preambles is64;

If 4≤the number of down-link synchronization signal blocks associated tothe same random access occasion<16, the maximum number of preambles is128;

If 16≤the number of down-link synchronization signal blocks associatedto the same random access occasion<32, the maximum number of preamblesis 256;

If 32≤the number of down-link synchronization signal blocks associatedto the same random access occasion, the maximum number of preambles is512.

In addition, it should be noted that there may be different numbers ofdown-link synchronization signal blocks associated to different randomaccess occasions. For this situation, the following methods may be used:

a. Using the maximum number of down-link synchronization signal blocksassociated to the same random access occasion, determine the maximumnumber of preambles in the above possible ways. The maximum number ofpreambles determined in this manner is the same for each synchronizationsignal block in the cell.

b. Determine the maximum number of preambles that may be used at aselected random access occasion according to the number of synchronizingsignal blocks associated to the selected random access occasion. Themaximum number of preambles determined in this manner may not be thesame for the synchronization signal blocks in the cell, but it mayensure that the number of preambles available to the terminal deviceswithin the coverage of each synchronization signal block are the same.

When notification and configuration of the maximum number of preamblesare performed in the above manner, the terminal device first obtains thenumber of down-link synchronization signal blocks associated to the samerandom access occasion according to the random access channelconfiguration information, and obtains the maximum number of preamblesaccording to a pre-defined association (for example, as shown in Table7). Moreover, the terminal device obtains the number of down-linksynchronization signal blocks associated to the same random accessoccasion according to the random access channel configurationinformation, obtains the number and index range of preambles availablefor the down-link synchronization signal block, and generates a preambleaccording to the root sequence configuration information and the cyclicshift configuration information in the preamble configurationinformation.

Specifically, if the foregoing manner a is adopted, the maximum numberof preambles is determined according to the maximum number of down-linksynchronization signal blocks associated to the same random accessoccasion obtained in the random access channel configuration. Afterdetermining the random access occasion according to the random accesschannel configuration information, the terminal device determines thenumber of preambles and the index range of preambles associated to eachdown-link synchronization signal block according to the number ofdown-link synchronization signal blocks mapped to the random accessoccasion.

If the foregoing manner b is adopted, the random access occasionassociated to the optimal or appropriate synchronization signal block isfirst determined, and the number of synchronization signal blocksassociated to the random access occasion is determined according to therandom access channel configuration in the RMSI or OSI. The maximumnumber of preambles at the random access occasion and the index range ofpreambles are determined according to the number of the synchronizationsignal blocks.

If it is assumed that the maximum number of preambles at a certainrandom access occasion is N_pre, and the random access occasioncorresponds to k synchronization signal blocks, then the number ofpreambles associated to each synchronization signal block is└N_(pre)/k┘. The Npre preambles are divided into k groups, and the indexrange of each preamble group is

$\left\lbrack {0,\ldots\;,{\left\lfloor \frac{N_{pre}}{k} \right\rfloor - 1}} \right\rbrack,\left\lbrack {\left\lfloor {N_{pre}\text{/}k} \right\rfloor,\ldots\;,{{2\left\lfloor \frac{N_{pre}}{k} \right\rfloor} - 1}} \right\rbrack,\ldots\;,\left\lbrack {{\left( {k - 1} \right)\left\lfloor \frac{N_{pre}}{k} \right\rfloor},\ldots\;,{{k\left\lfloor \frac{N_{pre}}{k} \right\rfloor} - 1}} \right\rbrack,$respectively.

In this grouping manner, when Npre is not an integer multiple of k,there will be some extra preambles that are not included in any group.In order to increase the preamble utilization, these preambles may beused for contention-free random access procedures or as preambles in anyone of the groups. The association between the synchronization signalblocks and the preamble groups may be as follows:

a. According to the index ordering of the synchronization signal blocksassociated to the same random access occasion, an association isestablished between the synchronization signal blocks and the preamblegroups with the same ordering index. For example, the 0thsynchronization signal block corresponds to group 0, the i-thsynchronization signal block corresponds to group i, and so on.

b. The following operation is performed on the index of thesynchronization signal block associated to the same random accessoccasion to obtain its index within the associated random accessoccasion: nss=└N_(ss)/k┘. Nss is the index of the synchronization signalblock, k is the number of synchronization signal blocks associated tothe random access occasion, and nss is the internal index of the randomaccess occasion. An association is established between thesynchronization signal blocks and the preamble groups with the sameindex, that is, an association is established between the nss-thsynchronization signal block and the nss-th preamble group.

In another embodiment of the present disclosure, a random access methodis provided as shown in FIG. 14, and the method is completed on a basestation side.

In another embodiment of the present disclosure, a calculation method ofa preamble identifier will be described in conjunction with a specificsystem. In this embodiment, the system operates at high frequency bandsand beam-forming techniques are used to traverse severe path losses athigh frequency bands. In order to notify the base station of thedown-link beam for transmitting the random access response, anassociation is established between the down-link synchronization signalblock, the random access occasion, and the preamble resource, and thebase station is notified of an appropriate down-link beam bytransmission of the preambles.

In this embodiment, the maximum number of preambles is notified in themanner of the foregoing embodiment. When sending a random accessresponse, it is necessary to add a random access preamble identifier inthe random access response. When the system supports a plurality ofmaximum numbers of preambles, the possible indication ways of thepreamble identifier are as follows:

a. Indicating the number of bits of the preamble identifier according tothe maximum number of preambles, and indicating the preamble identifieraccording to the number of bits of the preamble identifier. For example,the number of bits of the preamble identifier is configured and set inadvance according to Table 8:

TABLE 8 Determination manner of the number of bits of the preambleidentifier Maximum number Number of bits of the of preambles preambleidentifier 64 6 128 7 256 8 . . . . . .

Or the number of bits of preamble identifier is determined according tothe following rules:N_(pre)=┌log₂ M_(max)┐

Mmax is the maximum number of preambles, and Npre is the number of bitsof the preamble identifier.

b. Indicating the number of bits of the preamble identifier according toa maximum value of a plurality of maximum numbers of preambles, andindicating the preamble identifier according to the number of bits ofthe preamble identifier. For example, if the maximum value of aplurality of maximum numbers of preambles is Mmax, the number of bits ofthe preamble identifier may be selected as ┌log₂ M_(max)┐,alternatively, the number of bits of the preamble identifier may bedetermined according to the maximum value of a plurality of maximumnumbers of preambles.

c. Indicating the preamble identifier according to the down-link signalindication bits indicating the down-link signals and the pre-definedpreamble identifier bits. Specifically, using a pre-defined number ofbits of the preamble identifier, when there are a plurality ofsynchronization signal blocks associated to one random access occasion,and the configured maximum number of preambles is greater than thenumber of preambles that can be supported by the number of bits of thepreamble identifier, the random access preamble identifier is indicatedin the random access response in the manner of a preamble identifierplus synchronization signal block indication.

Specifically, the random access preamble identifier is indicated in thefollowing possible ways:

1. Indication bits for indicating synchronization signal blocks areadded in the random access response, and the transmitted preamble isindicated in the random access response by the indication bits and apre-defined preamble identifier. A simple example is as follows: therandom access identifier is pre-defined to 6 bits. If 4 synchronizationsignal blocks correspond to the same random access occasion, 2 bits areadded in the random access response for indicating the associatedsynchronization signal blocks. The transmitted preamble is indicated bythe 2-bit synchronization signal block indication information and the6-bit pre-defined random access identifier, as shown in FIG. 14.

2. The indication of the synchronization signal blocks is added forcalculating the random access radio network temporary identifierRA-RNTI, and the preamble indicated by the random access response isdetermined by the synchronization signal block indication in the RA-RNTIand the preamble identifier of the pre-defined length in the randomaccess response.

In another embodiment of the present disclosure, a configuration andindication method of a preamble of a contention-free random accessprocedure will be described in conjunction with a specific system. Inthis embodiment, the system operates at high frequency bands andbeam-forming techniques are used to traverse severe path losses at highfrequency bands. In order to notify the base station of the down-linkbeam for transmitting the random access response, an association isestablished between the down-link synchronization signal block/down-linkreference signal, the random access occasion, and the preamble resource,and the base station is notified of an appropriate down-link beam by thetransmission of the preamble.

For the contention-free random access procedure, the used preamble isconfigured through a down-link control channel or higher-layersignaling. For a system that supports a plurality of maximum numbers ofpreambles, the configuration of the preamble for a contention-freerandom access procedure may be implemented as follows:

a. Determining the number of indication bits of the preamble accordingto the maximum value of a plurality of maximum numbers of preambles. Forexample, the plurality of maximum numbers of preambles supported by thesystem are 64, 128, and 256, thus the number of indication bits of thepreamble is determined to 8 bits for 256.

b. For the preamble indication bits of a pre-defined length, thepreamble configured by the base station is indicated by the indicationbits of the down-link signals associated to the random access occasionand the preamble indication bits of the pre-defined length together. Asimple example is that one random access occasion corresponds to twodown-link signals, and 1-bit information is used for notification andconfiguration, and the random access indication is pre-defined to 6bits. Therefore, a 7-bit preamble index is jointly determined by the1-bit down-link signal indication and the random access indication bits.

The terminal device transmits the preamble at the random access occasionaccording to the preamble indication.

It should be noted that the down-link signal mentioned herein includesthe synchronization signal block, and may also include the channel stateinformation reference signal and the like.

FIG. 15 is a schematic flowchart of a random access method according toan embodiment of the present disclosure. In the method shown in FIG. 15,the base station transmits the configuration information of the maximumnumber of preambles to the terminal. Subsequently, the base stationdetects the random access preamble. After detecting the random accesspreamble, the random access response is transmitted.

The configuration information of the maximum number of preambles isincluded in the random access configuration information and/or thepreamble configuration information.

The present disclosure also provides a terminal device including aprocessor and a memory storing instructions that, when executed by theprocessor, cause the processor to perform the methods provided byforegoing exemplary embodiments herein.

A “terminal” or “terminal device” herein may refer to any terminalhaving wireless communication capabilities including but not limited toa mobile phone, a cellular phone, a smart phone or a personal digitalassistant (PDA), a portable computer, an image capture device such as adigital camera, gaming equipment, music storage and playback equipment,and any portable unit or terminal with wireless communicationcapabilities, or Internet facilities that allow wireless Internet accessand browsing.

The present disclosure also provides a base station including aprocessor and a memory storing instructions that, when executed by theprocessor, cause the processor to perform the methods described by theforegoing exemplary embodiments herein.

The term “base station” (BS) used herein may refer to eNB, eNodeB,NodeB, or base station transceiver (BTS), etc. depending on thetechnology and terminology used.

The “memory” herein may be any type suitable for the technicalenvironment herein, and may be implemented using any suitable datastorage technology, including but not limited to semiconductor-basedmemory devices, magnetic memory devices and systems, optical memorydevices and systems, fixed memory and removable memory.

The processor herein may be of any type suitable for the technicalenvironment herein, including but not limited to one or more of thefollowing: a general purpose computer, a special purpose computer, amicroprocessor, a digital signal processor DSP, and a processor based ona multi-core processor architecture.

The present disclosure also provides a machine readable medium storinginstructions that, when executed by a processor, cause the processor toperform the methods described in the foregoing exemplary embodimentsherein.

A “machine readable medium” as used herein should be taken to includeany medium or combination of media capable of storing instructionsexecuted by a machine, a device capable of temporarily or permanentlystoring instructions and data, and may include, but is not limited to,random access memory (RAM), read only memory (ROM), buffer memory, flashmemory, optical media, magnetic media, cache memory, other types ofmemory (e.g., erasable programmable read-only memory (EEPROM)) and/orany suitable combination thereof. A “machine readable medium” may referto a single storage apparatus or device and/or a “cloud-based” storagesystem or storage network that includes a plurality of storageapparatuses or devices.

The embodiments of the present disclosure provide a preambleconfiguration and indication method and related devices. In an explicitor implicit manner, the method provided in the embodiments of thepresent disclosure may flexibly configure the maximum number ofpreambles supported by the system and thus may more flexibly configurethe number of preambles allocated to the terminal device according tofactors such as application scenarios and the number of loads.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.Furthermore, the terms “include”, “comprise”, etc. as used hereinindicate the presence of stated features, steps, operations, and/orcomponents but do not preclude the presence or addition of one or moreother features, steps, operations, or components.

Each block in the flowcharts or block diagrams in the embodiments of thepresent disclosure may represent a hardware module, a program segment,or a part of code, and the above-mentioned module, program segment, orpart of code may include one or more executable instructions for theimplementation of the specified logic function. It should also be notedthat in some alternative implementations, the functions annotated in theflowcharts and blocks may also occur in a different order than thatannotated in the figures. For example, two consecutively representedblocks may actually be executed substantially in parallel, and they maysometimes be executed in the reverse order, depending on the functioninvolved. It is also to be noted that each block in the block diagramsor the flowcharts, and combinations of blocks in the block diagrams andthe flowcharts, may be implemented by a dedicated hardware-based systemthat performs specified functions or operations, or may be implementedby a combination of dedicated hardware and computer instructions.

The embodiments of the present disclosure have been described above.However, these embodiments are for illustrative purposes only and arenot intended to limit the scope of the present disclosure. Although therespective embodiments are separately described above, this does notmean that the measures in the respective embodiments cannot beadvantageously used in combination. The scope of the disclosure isdefined by the appended claims and their equivalents. Numerousalternatives and modifications may be made by those skilled in the artwithout departing from the scope of the present disclosure, and suchalternatives and modifications should all fall within the scope of thepresent disclosure.

It should be understood by one person of ordinary skill in the art thatsingular forms “a”, “an”, “the”, and “said” may be intended to includeplural forms as well, unless otherwise stated. It should be furtherunderstood that terms “include/including” used in this specificationspecify the presence of the stated features, integers, steps,operations, elements and/or components, but not exclusive of thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or combinations thereof. It shouldbe understood that, when a component is referred to as being “connectedto” or “coupled to” another component, it may be directly connected orcoupled to other elements or provided with intervening elementstherebetween. In addition, “connected to” or “coupled to” as used hereinmay include wireless connection or coupling. As used herein, the term“and/or” includes all or any of one or more associated listed items orcombinations thereof.

It should be understood by one person of ordinary skill in the art that,unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneperson of ordinary skill in the art to which the present disclosurebelongs. It should be further understood that terms, such as thosedefined in commonly used dictionaries, should be interpreted as having ameaning that is consistent with their meanings in the context of theprior art and will not be interpreted in an idealized or overly formalsense unless expressly so defined herein.

For a new system, a User Equipment (UE) may perform multiple preamblesbased random access, so that the probability of accessing the system bya user in one attempt may be increased. However, unlike the existingrandom access method based on a single preamble, during the transmissionof multiple preambles, the user equipment needs to clearly determinesequence choices and beam choices for transmitting multiple preambles,random access resources corresponding to the determined downlink beamsand a method for controlling a random access power and a power ramp.Otherwise, the user equipment cannot perform random access in a normallycontrollable manner.

The present disclosure provides a method for multiple preambles basedrandom access. During the random access process for a user equipmentbased on multiple preambles, it is proposed in the present disclosurethat the user equipment may determine respective preamble sequencesaccording to the selected multiple downlink beams, and calculaterespective preamble transmission counters and preamble power rampingcounters according to different downlink beams. Meanwhile, when the userequipment may perform multiple preambles based random access, the newmaximum number of preamble transmissions may be determined according tothe determined number of preambles that may be transmitted in oneattempt.

Specifically, in the present disclosure, scenarios involving themultiple preambles based random access include the followings.

1. The user equipment selects N (N=1) downlink transmitting beam, andthe user equipment may correspondingly transmit M (M>1) preambles basedon this downlink transmitting beam. That is, the UE transmits Mpreambles in one random access attempt, and the resources fortransmitting the M preambles correspond to the same selected downlinktransmitting beam. As shown in FIG. 17, N=1 and M=3 in the example.

2. The user equipment selects N (N>1) downlink transmitting beams, butthe user equipment may correspondingly transmit only M (M=1) preamblebased on each downlink transmitting beam. That is, the UE transmits Npreambles in one random access attempt, and the resources fortransmitting the N preambles one-to-one correspondence to the selected Ndownlink transmitting beams. As shown in FIG. 18, N=2 and M=1 in theexample.

3. The user equipment selects N (N>1) downlink transmitting beams, butthe user equipment may correspondingly transmit M (M>1) preambles basedon each downlink transmitting beam. That is, the UE transmits N*Mpreambles in one random access attempt, but the resources fortransmitting every M preambles correspond to the same selected downlinktransmitting beam. As shown in FIG. 19, N=2 and M=3 in the example.

It is to be noted that, N*M represents the maximum number of preamblesthat may be transmitted. However, since the UE may have received amatched Random Access Response (RAR) in advance, the UE does nottransmit N*M preambles actually. As shown in FIG. 20, the UE maydetermine from the random access resource configuration that at most 6preambles will be transmitted. However, since the UE receives a matchedRAR after transmitting the second preamble, the user may stoptransmitting subsequent possible preambles and then perform subsequenttransmission according to the scheduling in the received RAR. Therefore,in this case, the user actually transmits two preambles.

The index of a downlink transmitting beam may be represented by thefollowing information: a synchronization signal block index and/or aChannel State information-Reference Signal (CSI-RS) index. Thesynchronization signal block may include a primary synchronizationsignal, a secondary synchronization signal, and a broadcast signalcontaining a demodulation reference signal.

The UE may acquire a random access resource configuration (includingpossible random access channel resource configurations, a random accesspreamble resource configuration and a configuration of a mappingrelationship between the downlink beams and the random accessresources). The random access resource configuration also containsexplicit indication information of the transmission of multiplepreambles, and the value of N and/or the value of M are/is alsoconfigured. By the random access resource configuration, a base stationimplicitly informs the UE that it may transmit multiple preambles in oneattempt. For example, in the random access resource configuration, Mrandom access preamble resources corresponding to one downlinktransmitting beam are explicitly configured for the UE. When the UEobtains random access resources capable of transmitting M preambles, theUE considers that M preambles may be transmitted in one attempt. Thatis, the UE considers the configuration of multiple random accessresources as an indication of permitting the transmission of multiplepreambles.

When the user equipment determines that the multiple preambles basedrandom access is performed, the UE may perform the following operations.

1. Determining specific preamble sequences, specifically:

a. The UE determines the preamble sequences according to the number ofselected available downlink transmitting beams. That is, if the UEselects N downlink transmitting beams, the UE may select one preamblesequence for each downlink transmitting beam. That is, M preamblescorresponding to this downlink transmitting beam are transmitted by thesame preamble sequence.

b. The UE selects a preamble sequence. That is, all preambles in onerandom access attempt are transmitted by the same preamble sequence.

c. The UE determines the preamble sequences according to the explicitresource configuration information. If the resource configurationinformation explicitly indicates the preamble sequence used by the UE,the UE performs random access according to the indicated preamblesequence.

2. Determining specific uplink transmitting beams for transmittingmultiple preambles:

a. For M preambles corresponding to the same selected downlinktransmitting beam, the UE may randomly determine uplink transmittingbeams used by the M preambles with equal probability. However, for Mpreambles corresponding to each of the remaining downlink transmittingbeams, uplink transmitting beams for the M preambles corresponding toeach of the remaining downlink transmitting beams are determinedaccording to the uplink transmitting beams determined by the M preamblescorresponding to the first downlink transmitting beam.

b. For the transmission of preambles corresponding to all downlinktransmitting beams, uplink transmitting beams are randomly determined bythe UE with equal probability.

3. Determining a specific power ramping mode:

a. The UE determines a preamble power ramping counter for each of theselected downlink transmitting beams. That is, if the UE has N selecteddownlink transmitting beams and each downlink transmitting beam has Mpreambles, the UE may have at most N preamble power ramping counters,and the M preambles corresponding to each downlink transmitting beamshare the same preamble power ramping counter.

i. In the same random access process, when the UE performs a new randomaccess attempt, no matter whether or not the UE changes the uplinktransmitting beam, the preamble power ramping counter is increased by 1;

ii. In the same random access process, when the UE performs a new randomaccess attempt, for a same downlink transmitting beam, when less thanand/or equal to 1, or Y, or Y/x, or X, or X/x, or └X/x┘, or ┌X/x┐, or└Y/x┘, or ┌Y/x┐ uplink beams among the actually used Y uplink beams arechanged compared to the X actually used uplink transmitting beams in theprevious random access attempt, the preamble power ramping counter isincreased by 1, where the x is a ratio. For example, if x=2, M/xindicates that the preamble power ramping counter remains unchanged whenmore than half of uplink transmitting beams are changed; otherwise, thepreamble power ramping counter is increased by 1. In the presentdisclosure, └A┘ represents an integer not less than A, and ┌A┐represents an integer not greater than A.

b. The UE determines one preamble power ramping counter for thetransmission of each selected preamble.

i. For example, in the same random access process, total N*M preambleswill be transmitted, and each preamble transmission has its own preamblepower ramping counter. When the uplink transmitting beam fortransmitting this preamble is changed, the preamble power rampingcounter remains unchanged; otherwise, the preamble power ramping counteris increased by 1.

c. In one random access process, the UE uses only one preamble powerramping counter for the transmission of all preambles.

i. For example, in the same random access process, total N*M preambleswill be transmitted. When the UE performs a new random access attempt,when less than and/or equal to 1, or Y, or Y/x, or X, or X/x, or └X/x┘,or ┌X/x┐, or └Y/x┘, or ┌Y/x┐ uplink beams among the actually used Yuplink beams are changed compared to the X actually used uplinktransmitting beams in the previous random access attempt, the preamblepower ramping counter is increased by 1; otherwise, the preamble powerramping counter remains unchanged, where the x is a ratio. For example,if x=2, N*M/x indicates that the preamble power ramping counter remainsunchanged if more than half of uplink transmitting beams are changed;otherwise, the preamble power ramping counter is increased by 1.

4. Determining a specific power control mode:

a. The UE performs power control based on each of the selected downlinktransmitting beams. That is, during the transmission of M preamblescorresponding to each of the selected downlink transmitting beams, thetransmitting power is calculated by using a Path Loss (PL) obtained by asame corresponding downlink transmitting beam.

b. The UE calculates the transmitting power based on a unified PL,specifically:

i. the PL corresponding to the downlink transmitting beam having themaximum Reference Signal Received Power (RSRP) is selected;

ii. the PL corresponding to the downlink transmitting beam having theminimum RSRP is selected;

iii. an average of PLs corresponding to all downlink transmitting beamsis selected; and

iv. in accordance with a predefined or configured RSRP threshold, thedownlink transmitting beam having a PL not greater than or not less thanthe threshold is randomly selected with equal probability, and thetransmitting power is calculated by using the PL of this downlinktransmitting beam.

5. The user equipment determining the maximum number of transmissions.

a. If the preamble_max configured by the base station is in the randomaccess based on a transmission of a single preamble, the UE regards thepreamble_max as the maximum number of random access attempts, and onlyone preamble may be transmitted in each attempt; or, the UE directlyregards the preamble_max as the maximum number of preambles that may betransmitted by the UE in one random access process.

b. During the random access based on the transmission of multiplepreambles, the base station configures the maximum number of preamblesas preamble_max. When there are N selected downlink transmitting beamsand each downlink transmitting beam may correspondingly transmit Mpreambles, the preamble_max is regarded as the maximum number of randomaccess attempts, and N*M preambles may be transmitted in each attempt.When the UE performs a new random access attempt, the UE increases thepreamble transmission counter by 1. If the value of the preambletransmission counter at this time is equal to preamble_max+1, the UEreports a random access problem to the higher layer. Or, the maximumnumber of preambles that may be transmitted by the UE in one randomaccess process is calculated based on the preamble_max:preamble_max_new=preamble_max*N*M. When the UE performs a new randomaccess attempt, the UE actually transmits L preambles, and the UEincreases the preamble transmission counter by L. If the preambletransmission counter exceeds preamble_max*N*M at this time, the UEreports a random access problem to the higher layer. Or, the UE starts arandom access timer when it begins to transmit the first preamble; andwhen the random access timer expires, the UE reports a random accessproblem to the higher layer. Or, the UE simultaneously maintains thepreamble transmission counter and the random access timer; if thepreamble transmission counter exceeds a limit while the timer does notexpire, the UE reports a random access problem to the higher layer; and,if the preamble transmission counter does not exceed the limit while thetimer expires, the UE also reports the random access problem to thehigher layer.

6. The receiving a Random Access Response (RAR) message.

a. When the UE detects a matched RAR, the UE stops searching, then readsan uplink grant in the RAR and begins to prepare for subsequent uplinktransmission.

b. When the UE detects an RAR, the UE may continuously search within aconfigured RAR window. If multiple matched RARs are found,

i. the UE randomly selects an RAR with equal probability;

ii. the UE selects, according to the uplink grant, an RAR supporting theearliest subsequent uplink transmission; and

iii. the UE determines an RAR according to a Hybrid Automatic Repeat(HARQ) progress ID indicated in the RAR, specifically:

1) if there are multiple different HARQ progress IDs, the UE transmitscorresponding uplink data according to the uplink grant indicated in thecorresponding RAR; and

2) for a same HARQ progress ID, the UE randomly selects an RAR withequal probability, or the UE selects, according to the uplink grant, anRAR supporting the earliest subsequent uplink transmission.

In one embodiment, in a contention-free random access scenario, how toperform the multiple preambles based random access provided in thepresent disclosure will be described.

A UE acquires measurement reference signals configured by a basestation. The measurement reference signals include a synchronizationsignal block and/or a Channel State Information-Reference Signal(CSI-RS). The synchronization signal block may include a primarysynchronization signal, a secondary synchronization signal, and abroadcast signal containing a demodulation reference signal.

By measuring the configured measurement reference signals, the UEacquires a measurement result of the measurement reference signal, forexample, Reference Signal Received Power (RSRP), then:

1. The UE may feed back the measurement results of all the configuredmeasurement reference signals to the base station.

a. Handover scenario: a serving base station determines, according tothe feedback of the measurement results, whether the UE needs to performhandover; the serving base station informs a target base station of thefeedback result, and the target base station determines indexes of oneor more selected measurement reference signals; and, correspondingrandom access resources are configured for the one or more selectedmeasurement reference signals, and then informed to the serving basestation. The serving base station finally transmits the indexes of theone or more selected measurement reference signals and the configuredcorresponding random access resources to the UE through a downlinkchannel (a control channel or a shared channel).

b. Present cell scenario: A base station in the present cell determinesindexes of one or more selected measurement reference signals, andconfigures corresponding random access resources for the one or moreselected measurement reference signals. The base station in the presentcell finally transmits the indexes of the one or more selectedmeasurement reference signals and the configured corresponding randomaccess resources to the UE through the downlink channel (the controlchannel or the shared channel).

2. The UE may feed back, according to a predefined or configuredthreshold and to the base station, measurement results of allmeasurement reference signals greater than or not less than thethreshold, then:

a. Handover scenario: a serving base station determines, according tothe received feedback of the measurement results, whether the UE needsto perform handover, and informs a target base station of the feedbackresult.

i. The target base station determines indexes of one or more selectedmeasurement reference signals, configures corresponding random accessresources for the one or more selected measurement reference signals,and informs the serving base station of the corresponding random accessresources. The serving base station finally transmits the indexes of theone or more selected measurement reference signals and the configuredcorresponding random access resources to the UE through the downlinkchannel (the control channel or the shared channel).

ii. The target base station configures, according to the number offed-back measurement reference signals, corresponding random accessresources for all the fed-back measurement reference signals, andinforms the serving base station of the corresponding random accessresources. The serving base station finally transmits the indexes of allfed-back measurement reference signals and the configured correspondingrandom access resources to the UE through a downlink channel (a controlchannel or a shared channel).

b. Present cell scenario: A base station in the present cell determinesindexes of one or more selected measurement reference signals, andconfigures corresponding random access resources for the one or moreselected measurement reference signals. The base station in the presentcell finally transmits the indexes of the one or more selectedmeasurement reference signals and the configured corresponding randomaccess resources to the UE through the downlink channel (the controlchannel or the shared channel).

3. The UE may feed back the measurement results of all the configuredmeasurement reference signals to the base station, and feed back,according to a predefined or configured threshold and to the basestation, indexes of all measurement reference signals greater than ornot less than the threshold.

a. Handover scenario: the serving base station determines, according tothe received feedback of the measurement results, whether the UE needsto perform handover, and informs the target base station of the feedbackresult and the indexes of the measurement reference signals fed back bythe UE.

i. The target base station determines, from the indexes of the fed-backmeasurement reference signals, indexes of one or more selectedmeasurement reference signals, configures corresponding random accessresources for the one or more selected measurement reference signals,and informs the serving base station of the corresponding random accessresources. The serving base station finally transmits the indexes of theone or more selected measurement reference signals and the configuredcorresponding random access resources to the UE through the downlinkchannel (the control channel or the shared channel).

ii. The target base station configures, according to the indexes of themeasurement reference signals fed back by the UE, corresponding randomaccess resources for all the fed-back measurement reference signals, andinforms the serving base station of the corresponding random accessresources. The serving base station finally transmits the indexes of allfed-back measurement reference signals and the configured correspondingrandom access resources to the UE through the downlink channel (thecontrol channel or the shared channel).

b. Present cell scenario: the base station in the present celldetermines, from the indexes of the fed-back measurement referencesignals, indexes of one or more selected measurement reference signals,and configures corresponding random access resources for the one or moreselected measurement reference signals. The base station in the presentcell finally transmits the indexes of the one or more selectedmeasurement reference signals and the configured corresponding randomaccess resources to the UE through the downlink channel (the controlchannel or the shared channel).

By the above operations, the UE may obtain the random access resourcesconfigured by the base station and the indexes of correspondingmeasurement reference signals, including a mapping relationship betweenthe configured random access resources and the indexes of measurementreference signals. It may be stipulated that the indexes of measurementreference signals and the configured random access resources are in aone-to-one, one-to-N or N-to-one mapping relationship. It is alsopossible that the index of each measurement reference signal correspondsto a set of random access resource configuration information.

Specifically, in the present disclosure, scenarios involving themultiple preambles based random access include the followings.

1. The user equipment acquires the index of one configured downlinktransmitting beam and the corresponding random access resources; and,based on this downlink transmitting beam, the user equipment maycorrespondingly transmit M (M>1) preambles. That is, the UE transmits Mpreambles in one random access attempt, and the resources fortransmitting the M preambles correspond to the same downlinktransmitting beam.

2. The user equipment acquires N (N>1) configured downlink transmittingbeams and the corresponding random access resources; and, based on eachdownlink transmitting beam, the user equipment may correspondinglytransmit only one preamble. That is, the UE transmits N preambles in onerandom access attempt, and the resources for transmitting the Npreambles are in one-to-one correspondence to the N configured downlinktransmitting beams.

3. The user equipment acquires N (N>1) configured downlink transmittingbeams and the corresponding random access resources; and, based on eachdownlink transmitting beam, the user equipment may correspondinglytransmit M (M>1) preambles. That is, the UE transmits N*M preambles inone random access attempt, but the resources for transmitting every Mpreambles correspond to the same configured downlink transmitting beam.

After the UE acquires the random access resource configuration(including a possible random access channel resource configuration, arandom access preamble resource configuration, and a configuration ofthe mapping relationship between downlink transmitting beams and randomaccess resources):

1. the random access resource configuration also contains explicitindication information of the transmission of multiple preambles, andalso configures the value of N and/or the value of M; and

2. by the random access resource configuration, the base stationimplicitly informs the UE that it may transmit multiple preambles in onerandom access attempt. For example, in the random access resourceconfiguration, each configured downlink transmitting beam is mapped to Mpreamble resources and/or M random access channel resources; or, therandom access resource configuration corresponding to the index of eachconfigured downlink transmitting beam contains M preamble resourcesand/or M random access channel resources.

When the user equipment determines that the multiple preambles basedrandom access is performed, the UE may perform the following operations.

1. Determining specific preamble sequences, specifically:

a. The UE determines preamble sequences according to the number ofselected available downlink transmitting beams. If the UE configures Ndownlink transmitting beams, the UE may select one preamble sequence foreach downlink transmitting beam. That is, M preambles corresponding tothis downlink transmitting beam are transmitted by the same preamblesequence.

b. The UE selects one preamble sequence for all configured downlinktransmitting beams.

c. The UE determines preamble sequences according to the explicitresource configuration information. For example, if the resourceconfiguration information explicitly indicates a preamble sequence usedby the UE, the UE performs random access according to the indicatedpreamble sequence.

2. Determining specific uplink transmitting beams for transmittingmultiple preambles:

a. For M preambles corresponding to the same configured downlinktransmitting beam, the UE may randomly determine uplink transmittingbeams used by the M preambles with equal probability. However, for the Mpreambles corresponding to each of the remaining downlink transmittingbeams, uplink transmitting beams for the M preambles corresponding toeach of the remaining downlink transmitting beams are determinedaccording to the uplink transmitting beams determined by the M preamblescorresponding to the first downlink transmitting beam.

b. For the transmission of preambles corresponding to all downlinktransmitting beams, uplink transmitting beams are randomly determined bythe UE with equal probability.

3. Determining a specific power ramping mode:

a. The UE determines a preamble power ramping counter for each of theselected downlink transmitting beams. That is, if the UE has N selecteddownlink transmitting beams and there are M possibly transmittedpreambles corresponding to each downlink transmitting beam, the UE mayhave at most N preamble power ramping counters, and the M possiblepreambles corresponding to each downlink transmitting beam share a samepreamble power ramping counter. Then:

i. In a same random access process, when the UE performs a new randomaccess attempt, no matter whether or not the UE changes the uplinktransmitting beam, the preamble power ramping counter is increased by 1.

ii. In the same random access process, when the UE performs a new randomaccess attempt, among M preambles corresponding to a certain downlinktransmitting beam, if the UE will actually transmit total X preambles, Xuplink transmitting beams will be used; and, when total Y preambles aretransmitted by the UE in a new random access attempt, Y uplinktransmitting beams will be used.

a) When Y=X, and when less than and/or equal to 1, or X, or X/x, or└X/x┘, or ┌x/x┐ uplink beams among the Y uplink beams are changedcompared to the X uplink beams, the preamble power ramping counterremains unchanged; otherwise, the preamble power ramping counter isincreased by 1, where the x represents a ratio. For example, if x=2, X/xindicates that the preamble power ramping counter remains unchanged whenmore than half of uplink transmitting beams are changed compared to theactually used uplink transmitting beams in the previous random accessattempt; otherwise, the preamble power ramping counter is increasedby 1. For example, in the previous random access attempt, for a certaindownlink transmitting beam, the UE transmits X (X=3) preambles and uses3 uplink transmitting beams, for example, two beam 1 and one beam 2;however, in the current random access attempt, for the same downlinktransmitting beam, the UE also transmits Y (Y=3) preambles and also uses3 uplink transmitting beams. If there are one beam 1, one beam 2 and onebeam 3 at this time, it is indicated that only one beam is changed. Inthis case, if the rule is that the preamble power ramping counterremains unchanged when the number of changed beams exceeds └X/2┘=2,since 1<2, the UE needs to increase the preamble power ramping counterby 1.

b) When Y<X, and when less than and/or equal to 1, or Y, or Y/x, or X,or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐ uplink beams among the Yuplink beams are changed compared to the X uplink beams, the preamblepower ramping counter remains unchanged; otherwise, the preamble powerramping counter is increased by 1, where the x represents a ratio. Forexample, if x=2, X/x indicates that the preamble power ramping counterremains unchanged when more than half of uplink transmitting beams arechanged compared to the actually used uplink transmitting beams in theprevious random access attempt; otherwise, the preamble power rampingcounter is increased by 1. For example, in the previous random accessattempt, for a certain downlink transmitting beam, the UE transmits X(X=3) preambles and uses 3 uplink transmitting beams, for example, twobeam 1 and one beam 2; however, in the current random access attempt,for the same downlink transmitting beam, the UE transmits Y (Y=2)preambles and uses 2 uplink transmitting beams. If there are one beam 1and one beam 2 at this time, it is indicated that zero beam is changed.In this case, if the rule is that the preamble power ramping counterremains unchanged when the number of changed beams exceeds └Y/2┘=1,since 0<1, the UE needs to increase the preamble power ramping counterby 1. If there are one beam 3 and one beam 4 at this time, it isindicated that two beams are changed. In this case, if the rule is thatthe preamble power ramping counter remains unchanged when the number ofchanged beams exceeds └Y/2┘=1, since 2>1, the UE needs to remain thepreamble power ramping counter unchanged.

c) When Y>X, and when less than and/or equal to 1, or Y, or Y/x, or X,or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐ uplink beams among the Yuplink beams are changed compared to the X uplink beams, the preamblepower ramping counter remains unchanged; otherwise, the preamble powerramping counter is increased by 1, where the x represents a ratio. Forexample, if x=2, X/x indicates that the preamble power ramping counterremains unchanged when more than half of uplink transmitting beams arechanged compared to the actually used uplink transmitting beams in theprevious random access attempt; otherwise, the preamble power rampingcounter is increased by 1. For example, in the previous random accessattempt, for a certain downlink transmitting beam, the UE transmits X(X=3) preambles and uses 3 uplink transmitting beams, for example, twobeam 1 and one beam 2; however, in the current random access attempt,for the same downlink transmitting beam, the UE transmits Y (Y=4)preambles and uses 4 uplink transmitting beams. If there are one beam 1,one beam 2, one beam 3 and one beam 4 at this time, it is indicated thattwo beams are changed. In this case, if the rule is that the preamblepower ramping counter remains unchanged when the number of changed beamsexceeds └Y/2┘=2, since 2=2, the UE needs to increase the preamble powerramping counter by 1.

b. The UE determines independent preamble power ramping counters for thetransmission of all transmitted preambles.

i. For example, in the same random access process, if at most N*Mpreambles may be transmitted in one random access attempt, each preambletransmission has its own preamble power ramping counter.

a) When no RAR has been received before the transmission of thispreamble and when the uplink transmitting beam for transmitting thispreamble is changed, the preamble power ramping counter remainsunchanged; otherwise:

a. when no RAR has been received before the transmission of thispreamble and when the uplink transmitting beam for transmitting thispreamble remains unchanged, the preamble power ramping counter isincreased by 1; or,

b. when an RAR has been received before the transmission of thispreamble, the preamble power ramping counter is increased by 1.

c. In one random access process, the UE uses only one preamble powerramping counter for the transmission of all preambles.

i. For example, in the same random access process, in one random accessattempt, total X preambles are actually transmitted, and X uplinktransmitting beams are used. When the UE performs a new random accessattempt, total Y preambles are transmitted, and Y uplink transmittingbeams are used.

a) When Y=X, and when less than and/or equal to 1, or X, or X/x, or└X/x┘, or ┌X/x┌ uplink beams among the Y uplink beams are changedcompared to the X uplink beams, the preamble power ramping counterremains unchanged; otherwise, the preamble power ramping counter isincreased by 1, where the x represents a ratio. For example, if x=2, X/xindicates that the preamble power ramping counter remains unchanged whenmore than half of the uplink transmitting beams are changed; otherwise,the preamble power ramping counter is increased by 1. For example, inthe previous random access attempt, the UE transmits X (X=3) preamblesand uses 3 uplink transmitting beams, for example, two beam 1 and onebeam 2; however, in the current random access attempt, the UE alsotransmits Y (Y=3) preambles and also uses 3 uplink transmitting beams.If there are one beam 1, one beam 2 and one beam 3 at this time, it isindicated that only one beam is changed. In this case, if the rule isthat the preamble power ramping counter remains unchanged if the numberof changed beams exceeds └X/2┘=2, since 1<2, the UE needs to increasethe preamble power ramping counter by 1.

b) When Y<X, and when less than and/or equal to 1, or Y, or Y/x, or X,or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐ uplink beams among the Yuplink beams are changed compared to the X uplink beams, the preamblepower ramping counter remains unchanged; otherwise, the preamble powerramping counter is increased by 1, where the x represents a ratio. Forexample, if x=2, X/x indicates that the preamble power ramping counterremains unchanged when more than half of uplink transmitting beams arechanged compared to the actually used uplink transmitting beams in theprevious random access attempt; otherwise, the preamble power rampingcounter is increased by 1. For example, in the previous random accessattempt, the UE transmits X (X=3) preambles and uses 3 uplinktransmitting beams, for example, two beam 1 and one beam 2; however, inthe current random access attempt, the UE transmits Y (Y=2) preamblesand uses 2 uplink transmitting beams. If there are one beam 1 and onebeam 2 at this time, it is indicated that zero beam is changed. In thiscase, if the rule is that the preamble power ramping counter remainsunchanged when the number of changed beams exceeds └Y/2┘=1, since 0<1,the UE needs to increase the preamble power ramping counter by 1. Ifthere are one beam 3 and one beam 4 at this time, it is indicated thattwo beams are changed. In this case, if the rule is that the preamblepower ramping counter remains unchanged when the number of changed beamsexceeds └Y/2┘=1, since 2>1, the UE needs to remain the preamble powerramping counter unchanged.

c) When Y>X, and when less than and/or equal to 1, or Y, or Y/x, or X,or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┐Y/x┐ uplink beams among the Yuplink beams are changed compared to the X uplink beams, the preamblepower ramping counter remains unchanged; otherwise, the preamble powerramping counter is increased by 1, where the x represents a ratio. Forexample, if x=2, X/x indicates that the preamble power ramping counterremains unchanged when more than half of uplink transmitting beams arechanged compared to the actually used uplink transmitting beams in theprevious random access attempt; otherwise, the preamble power rampingcounter is increased by 1. For example, in the previous random accessattempt, the UE transmits X (X=3) preambles and uses 3 uplinktransmitting beams, for example, two beam 1 and one beam 2; however, inthe current random access attempt, the UE transmits Y (Y=4) preamblesand uses 4 uplink transmitting beams. If there are one beam 1, one beam2, one beam 3 and one beam 4 at this time, it is indicated that twobeams are changed. In this case, if the rule is that the preamble powerramping counter remains unchanged if the number of changed beams exceeds└Y/2┘=2, since 2=2, the UE needs to increase the preamble power rampingcounter by 1.

4. Determining a specific power control mode:

a. The UE performs power control based on each of the configureddownlink transmitting beams. That is, during the transmission of Mpreambles corresponding to each of the selected downlink transmittingbeams, the transmitting power is calculated by using a Path Loss (PL)obtained by a same corresponding downlink transmitting beam.

b. The UE calculates the transmitting power based on a unified PL,specifically:

i. the PL corresponding to the downlink transmitting beam having themaximum Reference Signal Received Power (RSRP) is selected;

ii. the PL corresponding to the downlink transmitting beam having theminimum RSRP is selected;

iii. an average of PLs corresponding to all downlink transmitting beamsis selected; and

iv. in accordance with a predefined or configured RSRP threshold, thedownlink transmitting beam having a PL not greater than or not less thanthe threshold is randomly selected with equal probability, and thetransmitting power is calculated by using the PL of this downlinktransmitting beam.

5. The user equipment determining the maximum number of transmissions.

a. In the random access based on the transmission of a single preamble,the UE regards the preamble_max configured by the base station as themaximum number of random access attempts, and only one preamble may betransmitted in each attempt; or, the UE directly regards thepreamble_max as the maximum number of preambles that may be transmittedby the UE in one random access process.

b. During the random access based on the transmission of multiplepreambles, the UE regards preamble_max configured by the base station asthe maximum number of random access attempts, and at most N*M preamblesmay be transmitted in each attempt. When the UE prepares for a newrandom access attempt, the UE will increase the preamble transmissioncounter by 1. When the preamble transmission counter exceedspreamble_max or is equal to preamble_max+1, the UE reports a randomaccess problem to the higher layer. Or, the UE obtains, according to thepreamble_max configured by the base station, the maximum numberpreamble_max_new of preambles that may be transmitted by the UE in onerandom access process. In this case, preamble_max_new=preamble_max*N*M.When the number of preambles transmitted by the UE exceeds thepreamble_max_new, the UE reports a random access problem to the higherlayer. In addition, the UE may start a random access timer when itbegins to transmit the first preamble. When the random access timerexpires, the UE reports a random access problem to the higher layer. Or,the UE simultaneously maintains the random access preamble transmissioncounter and the random access timer, if the preamble transmissioncounter exceeds a limit while the timer does not expire, the UE reportsa random access problem to the higher layer; and, if the preambletransmission counter does not exceed the limit while the timer expires,the UE also reports a random access problem to the higher layer.

6. The UE receiving a Random Access Response (RAR) message.

a. The UE stops searching when detecting a matched RAR, then reads anuplink grant in the RAR and begins to prepare for subsequent uplinktransmission.

b. When the UE detects an RAR, the UE may continuously search within aconfigured RAR window. If multiple matched RARs are found,

i. the UE randomly selects an RAR with equal probability;

ii. the UE selects, according to the uplink grant, an RAR supporting theearliest subsequent uplink transmission; and

iii. the UE determines an RAR according to an HARQ progress ID indicatedin the RAR, specifically:

1) if there are multiple different HARQ progress IDs, the user transmitscorresponding uplink data according to the uplink grant indicated in thecorresponding RAR; and

2) for a same HARQ progress ID, the UE randomly selects an RAR withequal probability, or the UE selects, according to the uplink grant, anRAR supporting the earliest subsequent uplink transmission.

In another embodiment, in a contention-based random access scenario, howto perform the multiple preambles based random access provided in thepresent disclosure will be described.

A UE reads, from the random access configuration information transmittedin a downlink channel (a broadcast channel or a shared channel or acontrol channel), available random access resources including randomaccess channel resources, random access preamble resources, and apossible mapping relationship between measurement reference signals andrandom access resources) in the present cell. By using the measurementresults of the measurement reference signals (for example, an RSRP, aSignal-to-Noise Ratio (SNR), a Block Error Ratio (BLER), etc.,), the UEmay perform the following operations.

1. Selecting indexes of N measurement reference signals having theoptimal measurement result (for example, maximum RSRP, maximum SNR,minimum BLER, etc.,); and

2. based on a preset configured threshold, selecting indexes of allmeasurement reference signals having a measurement result satisfying thethreshold (for example, an RARP greater than the threshold, an SNRgreater than the threshold, a BLER less than the threshold, etc.,); and

3. based on a preset or configured threshold, selecting indexes of Nmeasurement reference signals having a measurement result satisfying thethreshold (for example, an RARP greater than the threshold, an SNRgreater than the threshold, a BLER less than the threshold, etc.,).

When the UE determines the indexes of one or more selected measurementreference signals (i.e., indexes of downlink transmitting bearers), acorresponding random resource configuration may be determined. After theUE acquires the random access resource configuration (including apossible random access channel resource configuration, a random accesspreamble resource configuration, and a configuration of the mappingrelationship between downlink beam indexes and random access resources):

1. the random access resource configuration also contains explicitindication information of the transmission of multiple preambles, andthe value of N and/or the value of M; and

2. by the random access resource configuration, a base stationimplicitly informs the UE that it may transmit multiple preambles in oneattempt. For example, in the random access resource configuration, Mrandom access preamble resources corresponding to one downlinktransmitted beam are explicitly configured for the UE. When the UEobtains random access resources capable of transmitting M preambles, theUE considers that M preambles may be transmitted in one attempt. Thatis, the UE considers the configuration of multiple random accessresources as an indication of permitting the transmission of multiplepreambles.

Specifically, in the present disclosure, scenarios involving themultiple preambles based random access include the followings.

1. The user equipment selects one downlink transmitting beam, and theuser equipment may correspondingly transmit M (M>1) preambles based onthis downlink transmitting beam. That is, the UE transmits M preamblesin one random access attempt, and the resources for transmitting the Mpreambles correspond to the same selected downlink transmitting beam.

2. The user equipment selects N (N>1) downlink transmitting beams, butthe user equipment may correspondingly transmit only 1 preamble based oneach downlink transmitting beam. That is, the UE transmits N preamblesin one random access attempt, and the resources for transmitting the Npreambles are in one-to-one correspondence to the selected N downlinktransmitting beams.

3. The user equipment selects N (N>1) downlink transmitting beams, butthe user equipment may correspondingly transmit M (M>1) preambles basedon each downlink transmitting beam. That is, the UE transmits N*Mpreambles in one random access attempt, but the resources fortransmitting every M preambles correspond to the same selected downlinktransmitting beam.

When the user equipment determines that the multiple preambles basedrandom access is performed, the UE may perform the following operations.

1. Determining specific preamble sequences, specifically:

a. The UE determines preamble sequences according to the number ofselected available downlink transmitting beams. If the UE selects Ndownlink transmitting beams, the UE may select one preamble sequence foreach downlink transmitting beam. That is, M preambles corresponding tothis downlink transmitting beam are transmitted by the same preamblesequence.

b. The UE selects a preamble sequence. That is, all preambles in onerandom access attempt are transmitted by the same preamble sequence.

c. The UE determines preamble sequences according to the explicitresource configuration information. If the resource configurationinformation explicitly indicates a preamble sequence used by the UE forthe index of the downlink transmitting index, the UE performs randomaccess according to the indicated preamble sequence. If multipleavailable preamble sequences are indicated, the UE randomly selects apreamble sequence with equal probability.

2. Determining specific uplink transmitting beams for transmittingmultiple preambles:

a. For M preambles corresponding to the same selected downlinktransmitting beam, the UE may randomly determine uplink transmittingbeams used by the M preambles with equal probability. However, for Mpreambles corresponding to each of the remaining downlink transmittingbeams, uplink transmitting beams for the M preambles corresponding toeach of the remaining downlink transmitting beams are determinedaccording to the uplink transmitting beams determined by the M preamblescorresponding to the first downlink transmitting beam.

b. For the transmission of preambles corresponding to all downlinktransmitting beams, uplink transmitting beams are randomly determined bythe UE with equal probability.

3. Determining a specific power ramping mode:

a. The UE determines a preamble power ramping counter for each of theselected downlink transmitting beams. That is, if the UE has N selecteddownlink transmitting beams and there are M possibly transmittedpreambles corresponding to each downlink transmitting beam, the UE mayhave at most N preamble power ramping counters, and the M possiblepreambles corresponding to each downlink transmitting beam share a samepreamble power ramping counter. Then:

ii. in the same random access process, when the UE performs a new randomaccess attempt, no matter whether or not the UE changes the uplinktransmitting beam, the preamble power ramping counter is increased by 1;

iii. In the same random access process, when the UE performs a newrandom access attempt, among M preambles corresponding to a certaindownlink transmitting beam, if the UE will actually transmit total Xpreambles, X uplink transmitting beams will be used; and, when total Ypreambles are transmitted by the UE in a new random access attempt, Yuplink transmitting beams will be used.

a) When Y=X, and when less than and/or equal to 1, or X, or X/x, or└X/x┘, or ┌X/x┐ uplink beams among the Y uplink beams are changedcompared to the X uplink beams, the preamble power ramping counterremains unchanged; otherwise, the preamble power ramping counter isincreased by 1, where the x represents a ratio. For example, if x=2, X/xindicates that the preamble power ramping counter remains unchanged whenmore than half of uplink transmitting beams are changed compared to theactually used uplink transmitting beams in the previous random accessattempt; otherwise, the preamble power ramping counter is increasedby 1. For example, in the previous random access attempt, for a certaindownlink transmitting beam, the UE transmits X (X=3) preambles and uses3 uplink transmitting beams, for example, two beam 1 and one beam 2;however, in the current random access attempt, for the same downlinktransmitting beam, the UE also transmits Y (Y=3) preambles and also uses3 uplink transmitting beams. If there are one beam 1, one beam 2 and onebeam 3 at this time, it is indicated that only one beam is changed. Inthis case, if the rule is that the preamble power ramping counterremains unchanged when the number of changed beams exceeds └X/2┘=2,since 1<2, the UE needs to increase the preamble power ramping counterby 1.

b) When Y<X, and when less than and/or equal to 1, or Y, or Y/x, or X,or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐ uplink beams among the Yuplink beams are changed compared to the X uplink beams, the preamblepower ramping counter remains unchanged; otherwise, the preamble powerramping counter is increased by 1, where the x represents a ratio. Forexample, if x=2, X/x indicates that the preamble power ramping counterremains unchanged when more than half of uplink transmitting beams arechanged compared to the actually used uplink transmitting beams in theprevious random access attempt; otherwise, the preamble power rampingcounter is increased by 1. For example, in the previous random accessattempt, for a certain downlink transmitting beam, the UE transmits X(X=3) preambles and uses 3 uplink transmitting beams, for example, twobeam 1 and one beam 2; however, in the current random access attempt,for the same downlink transmitting beam, the UE transmits Y (Y=2)preambles and uses 2 uplink transmitting beams. If there are one beam 1and one beam 2 at this time, it is indicated that zero beam is changed.In this case, if the rule is that the preamble power ramping counterremains unchanged when the number of changed beams exceeds └Y/2┘=1,since 0<1, the UE needs to increase the preamble power ramping counterby 1. If there are one beam 3 and one beam 4 at this time, it isindicated that two beams are changed. In this case, if the rule is thatthe preamble power ramping counter remains unchanged when the number ofchanged beams exceeds └Y/2┘=1, since 2>1, the UE needs to remain thepreamble power ramping counter unchanged.

c) When Y>X, and when less than and/or equal to 1, or Y, or Y/x, or X,or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐ uplink beams among the Yuplink beams are changed compared to the X uplink beams, the preamblepower ramping counter remains unchanged; otherwise, the preamble powerramping counter is increased by 1, where the x represents a ratio. Forexample, if x=2, X/x indicates that the preamble power ramping counterins unchanged when more than half of uplink transmitting beams arechanged compared to the actually used uplink transmitting beams in theprevious random access attempt; otherwise, the preamble power rampingcounter is increased by 1. For example, in the previous random accessattempt, for a certain downlink transmitting beam, the UE transmits X(X=3) preambles and uses 3 uplink transmitting beams, for example, twobeam 1 and one beam 2; however, in the current random access attempt,for the same downlink transmitting beam, the UE transmits Y (Y=4)preambles and uses 4 uplink transmitting beams. If there are one beam 1,one beam 2, one beam 3 and one beam 4 at this time, it is indicated thattwo beams are changed. In this case, if the rule is that the preamblepower ramping counter remains unchanged when the number of changed beamsexceeds └Y/2┘=2, since 2=2, the UE needs to increase the preamble powerramping counter by 1.

b. The UE determines independent preamble power ramping counters for thetransmission of all transmitted preambles.

iv. For example, in the same random access process, if at most N*Mpreambles may be transmitted in one random access attempt, each preambletransmission has its own preamble power ramping counter.

a) When no RAR has been received before the transmission of thispreamble and when the uplink transmitting beam for transmitting thispreamble is changed, the preamble power ramping counter remainsunchanged; otherwise:

a. when no RAR has been received before the transmission of thispreamble and when the uplink transmitting beam for transmitting thispreamble remains unchanged, the preamble power ramping counter isincreased by 1; or,

b. when an RAR has been received before the transmission of thispreamble, the preamble power ramping counter is increased by 1.

c. In one random access process, the UE uses only one preamble powercounter for the transmission of all preambles.

v. For example, in the same random access process, in one random accessattempt, total X preambles are actually transmitted, and X uplinktransmitting beams are used. When the UE performs a new random accessattempt, total Y preambles are transmitted, and Y uplink transmittingbeams are used.

a) When Y=X, and when less than and/or equal to 1, or X, or X/x, or└X/x┘, or ┌X/x┐ uplink beams among the Y uplink beams are changedcompared to the X uplink beams, the preamble power ramping counterremains unchanged; otherwise, the preamble power ramping counter isincreased by 1, where the x represents a ratio. For example, if x=2, X/xindicates that the preamble power ramping counter remains unchanged whenmore than half of the uplink transmitting beams are changed; otherwise,the preamble power ramping counter is increased by 1. For example, inthe previous random access attempt, the UE transmits X (X=3) preamblesand uses 3 uplink transmitting beams, for example, two beam 1 and onebeam 2; however, in the current random access attempt, the UE alsotransmits Y (Y=3) preambles and also uses 3 uplink transmitting beams,If there are one beam 1, one beam 2 and one beam3 at this time, it isindicated that only one beam is changed. In this case, if the rule isthat the preamble power ramping counter remains unchanged if the numberof changed beams exceeds └X/2┘=2, since 1<2, the UE needs to increasethe preamble power ramping counter by 1.

b) When Y<X, and when less than and/or equal to 1, or Y, or Y/x, or X,or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐ uplink beams among the Yuplink beams are changed compared to the X uplink beams, the preamblepower ramping counter remains unchanged; otherwise, the preamble powerramping counter is increased by 1, where the x represents a ratio. Forexample, if x=2, X/x indicates that the preamble power ramping counterremains unchanged when more than half of uplink transmitting beams arechanged compared to the actually used uplink transmitting beams in theprevious random access attempt; otherwise, the preamble power rampingcounter is increased by 1. For example, in the previous random accessattempt, the UE transmits X (X=3) preambles and uses 3 uplinktransmitting beams, for example, two beam 1 and one beam 2; however, inthe current random access attempt, the LE transmits Y (Y=2) preamblesand uses 2 uplink transmitting beams. If there are one beam 1 and onebeam 2 at this time, it is indicated that zero beam is changed. In thiscase, if the rule is that the preamble power ramping counter remainsunchanged when the number of changed beams exceeds └Y/2┘=1, since 0<1,the UE needs to increase the preamble power ramping counter by 1. Ifthere are one beam 3 and one beam 4 at this time, it is indicated thattwo beams are changed. In this case, if the rule is that the preamblepower ramping counter remains unchanged when the number of changed beamsexceeds └Y/2┘=1, since 2>1, the UE needs to remain the preamble powerramping counter unchanged.

c) When Y>X, and when less than and/or equal to 1, or Y, or Y/x, or X,or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐ uplink beams among the Yuplink beams are changed compared to the X uplink beams, the preamblepower ramping counter remains unchanged; otherwise, the preamble powerramping counter is increased by 1, where the x represents a ratio. Forexample, if x=2, X/x indicates that the preamble power ramping counterremains unchanged when more than half of uplink transmitting beams arechanged compared to the actually used uplink transmitting beams in theprevious random access attempt; otherwise, the preamble power rampingcounter is increased by 1. For example, in the previous random accessattempt, the UE transmits X (X=3) preambles and uses 3 uplinktransmitting beams, for example, two beam 1 and one beam 2; however, inthe current random access attempt, the UE transmits Y (Y=4) preamblesand uses 4 uplink transmitting beams. If there are one beam 1, one beam2, one beam 3 and one beam 4 at this time, it is indicated that twobeams are changed. In this case, if the rule is that the preamble powerramping counter remains unchanged if the number of changed beams exceeds└Y/2┘=2, since 2=2, the UE needs to increase the preamble power rampingcounter by 1.

4. Determining a specific power control mode:

a. The UE performs power control based on each of the selected downlinktransmitting beams. That is, during the transmission of M preamblescorresponding to each of the selected downlink transmitting beams, thetransmitting power is calculated by using a Path Loss (PL) obtained by asame corresponding downlink transmitting beam.

b. The UE calculates the transmitting power based on a unified PL,specifically:

i. the PL corresponding to the downlink transmitting beam having themaximum Reference Signal Received Power (RSRP) is selected;

ii. the PL corresponding to the downlink transmitting beam having theminimum RSRP is selected;

iii. an average of PLs corresponding to all downlink transmitting beamsis selected; and

iv. in accordance with a predefined or configured RSRP threshold, thedownlink transmitting beam having a PL not greater than or not less thanthe threshold is randomly selected with equal probability, and thetransmitting power is calculated by using the PL of this downlinktransmitting beam.

5. The user equipment determining the maximum number of transmissions.

a. In the random access based on the transmission of a single preamble,the UE regards the preamble_max configured by the base station as themaximum number of random access attempts, and only one preamble may betransmitted in each attempt; or, the UE directly regards thepreamble_max as the maximum number of preambles that may be transmittedby the UE in one random access process.

b. During the random access based on the transmission of multiplepreambles, the UE regards the preamble_max configured by the basestation as the maximum number of random access attempts, and at most N*Mpreambles may be transmitted in each attempt. Or, the UE obtains,according to the preamble_max configured by the base station, themaximum number preamble_max_new of preambles that may be transmitted bythe UE in one random access process. In this case,preamble_max_new=preamble_max*N*M. When the number of preamblestransmitted by the UE exceeds the preamble_max_new, the UE reports arandom access problem to the higher layer. Or, the UE starts a randomaccess timer when it begins to transmit the first preamble. When therandom access timer expires, the UE reports a random access problem tothe higher layer. Or, the UE simultaneously maintains the random accesspreamble transmission counter and the random access timer, if thepreamble transmission counter exceeds a limit while the timer does notexpire, the UE reports a random access problem to the higher layer; and,if the preamble transmission counter does not exceed the limit while thetimer expires, the UE also reports a random access problem to the higherlayer.

6. The UE receiving a Random Access Response (RAR) message.

a. The UE stops searching when detecting a matched RAR, then reads anuplink grant in the RAR and begins to prepare for subsequent uplinktransmission.

b. When the UE detects an RAR, the UE may continuously search within aconfigured RAR window. If multiple matched RARs are found,

i. the UE randomly selects an RAR with equal probability;

ii. the UE selects, according to the uplink grant, an RAR supporting theearliest subsequent uplink transmission; and

iii. the UE determines an RAR according to an progress ID indicated inthe RAR, specifically:

1) if there are multiple different HARQ progress IDs, the user transmitscorresponding uplink data according to the uplink grant indicated in thecorresponding RAR; and

2) for a same HARQ progress ID, the UE randomly selects an RAR withequal probability, or the UE selects, according to the uplink grant, anRAR supporting the earliest subsequent uplink transmission.

In another embodiment, two cases of acquiring the random access resourceconfiguration by the UE have been described in the above twoembodiments. In one case, the UE reports the measurement result, and thebase station configures corresponding random access resources; and inthe other case, the UE reads the configuration of the base station toacquire all possible d m access resource configurations, then selectsindexes of measurement reference signals (i.e., downlink transmittingbeams) according to its own measurement result, and eventually obtainsthe random access resources selected by itself. However, for the randomaccess in an unlicensed spectrum, the UE needs to perform LBT (ListenBefore Talk) on possible random access channels. That is, the UEattempts to receive signals on a channel, on which signals are to betransmitted, within a period of time before the real transmission ofsignals. If the received signal energy is not less than a preset orconfigured threshold, the UE considers that this channel has beenoccupied, the LBT is failed, and the UE may give up this transmission.In this embodiment, the case where LBT is performed in the unlicensedspectrum will be taken into consideration.

Specifically, in the present disclosure, scenarios involving themultiple preambles based random access include the followings.

1. The user equipment selects one downlink transmitting beam, and theuser equipment may correspondingly transmit at most M (M>1) preamblesbased on this downlink transmitting beam. That is, the UE transmits atmost M preambles in one random access attempt, and the resources fortransmitting the M preambles correspond to the same selected downlinktransmitting beam. As shown in FIG. 21, the UE selects one downlinktransmitting beam from the random access configuration, and it may bedetermined that three random access channels are transmitted by thecorresponding random resources. However, since the LBT on the channel 1is failed and the LBT on the channels 2 and 3 is successful, the UEactually transmits only two preambles.

2. The user equipment selects N (N>1) downlink transmitting beams, butthe user equipment may correspondingly transmit at most one preamblesbased on each downlink transmitting beam. That is, the UE transmits atmost N preambles in one random access attempt, and the resources fortransmitting the N preambles are in one-to-one corresponding to the Nselected downlink transmitting beams. As shown in FIG. 22, the UEselects two downlink transmitting beams from the random accessconfiguration, and it may be determined that one random access channelis transmitted by the random resources corresponding to each downlinktransmitting beam. However, since the LBT on the channel 1 is failed andthe LBT on the channel 2 is successful, the UE actually transmits onlyone preamble.

3. The user equipment selects N (N>1) downlink transmitting beams, butthe user equipment may correspondingly transmit at most M (M>1)preambles based on each downlink transmitting beam. That is, the UEtransmits at most N*M preambles in one random access attempt, but theresources for transmitting every M preambles correspond to the sameselected downlink transmitting beam. As shown in FIG. 23, from theperspective of the resource configuration, in the case where the UEselects SSB1, at most three preambles may be transmitted. However, sincethe LBT on the random access channel 3 is failed, the UE transmits onlytwo preambles in three random access channels corresponding to the SSB1.Similarly, the UE transmits only one preamble in three random accesschannels corresponding to SSB2. Therefore, the UE actually transmitsthree preambles in one random access attempt.

After the UE acquires the random access resource configuration(including a possible random access channel resource configuration, arandom access preamble resource configuration, and a configuration ofthe mapping relationship between downlink beams and random accessresources):

1. the random access resource configuration also contains explicitindication information of the transmission of multiple preambles, andthe value of N and/or the value of M; and

2. by the random access resource configuration, the base stationimplicitly informs the UE that it may transmit multiple preambles in oneattempt. For example, in the random access resource configuration, Mrandom access preamble resources corresponding to one downlinktransmitting beam are explicitly configured for the UE. When the UEobtains random access resources capable of transmitting M preambles, theUE considers that M preambles may be transmitted in one attempt. Thatis, the UE considers the configuration of multiple random accessresources as an indication of permitting the transmission of multiplepreambles.

When the user equipment determines that the multiple preambles basedrandom access is performed, the UE may perform the following operations.

1. Determining specific preamble sequences, specifically:

a. The UE determines preamble sequences according to the number ofselected available downlink transmitting beams. If the UE selects Ndownlink transmitting beams, the UE may select one preamble sequence foreach downlink transmitting beam. That is, M preambles corresponding tothis downlink transmitting beam are transmitted by the same preamblesequence.

b. The UE selects a preamble sequence. That is, all preambles in onerandom access attempt are transmitted by the same preamble sequence.

c. The UE determines preamble sequences according to the explicitresource configuration information. If the resource configurationinformation explicitly indicates a preamble sequence used by the UE, theUE performs random access according to the indicated preamble sequence.

2. Determining specific uplink transmitting beams for transmittingmultiple preambles:

a. For M possible preambles corresponding to the same selected downlinktransmitting beam, the UE may randomly determine uplink transmittingbeams used by the M preambles with equal probability. However, for Mpreambles corresponding to each of the remaining downlink transmittingbeams, uplink transmitting beams for the M preambles corresponding toeach of the remaining downlink transmitting beams are determinedaccording to the uplink transmitting beams determined by the M preamblescorresponding to the first downlink transmitting beam.

b. For the transmission of preambles corresponding to all downlinktransmitting beams, uplink transmitting beams are randomly determined bythe UE with equal probability.

3. Determining a specific power ramping mode:

a. The UE determines a preamble power ramping counter for each of theselected downlink transmitting beams. That is, if the UE has N selecteddownlink transmitting beams and there are M possibly transmittedpreambles corresponding to each downlink transmitting beam, the UE mayhave at most N preamble power ramping counters, and the M possiblepreambles corresponding to each downlink transmitting beam share a samepreamble power ramping counter. Then:

vi. In the same random access process, when the UE performs a new randomaccess attempt, no matter whether or not the UE changes the uplinktransmitting beam, the preamble power ramping counter is increased by 1.

vii. In the same random access process, when the UE performs a newrandom access attempt, among M preambles corresponding to a certaindownlink transmitting beam, if the UE will actually transmit total Xpreambles, X uplink transmitting beams will be used; and, when total Ypreambles are transmitted by the UE in a new random access attempt, Yuplink transmitting beams will be used.

a) When Y=X, and when less than and/or equal to 1, or X, or X/x, or└X/x┘, or ┌X/x┐ uplink beams among the Y uplink beams are changedcompared to the X uplink beams, the preamble power ramping counterremains unchanged; otherwise, the preamble power ramping counter isincreased by 1, where the x represents a ratio. For example, if x=2, X/xindicates that the preamble power ramping counter remains unchanged whenmore than half of uplink transmitting beams are changed compared to theactually used uplink transmitting beams in the previous random accessattempt; otherwise, the preamble power ramping counter is increasedby 1. For example, in the previous random access attempt, for a certaindownlink transmitting beam, the UE transmits X (X=3) preambles and uses3 uplink transmitting beams, for example, two beam 1 and one beam 2;however, in the current a random access attempt, for the same downlinktransmitting beam, the UE also transmits Y (Y=3) preambles and also uses3 uplink transmitting beams. If there are one beam 1, one beam 2 and onebeam 3 at this time, it is indicated that only one beam is changed. Inthis case, if the rule is that the preamble power ramping counterremains unchanged when the number of changed beams exceeds └X/2┘=2,since 1<2, the UE needs to increase the preamble power ramping counterby 1.

b) When Y<X, and when less than and/or equal to 1, or Y, or Y/x, or X orX/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐ uplink beams among the Yuplink beams are changed compared to the X uplink beams, the preamblepower ramping counter remains unchanged; otherwise, the preamble powerramping counter is increased by 1, where the x represents a ratio. Forexample, if x=2, X/x indicates that the preamble power ramping counterremains unchanged when more than half of uplink transmitting beams arechanged compared to the actually used uplink transmitting beams in theprevious random access attempt; otherwise, the preamble power rampingcounter is increased by 1. For example, in the previous random accessattempt, for a certain downlink transmitting beam, the UE transmits X(X=3) preambles and uses 3 uplink transmitting beams, for example, twobeam 1 and one beam 2; however, in the current random access attempt,for the same downlink transmitting beam, the UE transmits Y (Y=2)preambles and uses 2 uplink transmitting beams. If there are one beam 1and one beam 2 at this time, it is indicated that zero beam is changed.In this case, if the rule is that the preamble power ramping counterremains unchanged when the number of changed beams exceeds └Y/2┘=1,since 0<1, the UE needs to increase the preamble power ramping counterby 1. If there are one beam 3 and one beam 4 at this time, it isindicated that two beams are changed. In this case, if the rule is thatthe preamble power ramping counter remains unchanged when the number ofchanged beams exceeds └Y/2┘=2, since 2>1, the UE needs to remain thepreamble power ramping counter unchanged.

c) When Y>X, and when less than and/or equal to 1, or Y, or Y/x, or X,or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐ uplink beams among the Yuplink beams are changed compared to the X uplink beams, the preamblepower ramping counter remains unchanged; otherwise, the preamble powerramping counter is increased by 1, where the x represents a ratio. Forexample, if x=2, X/x indicates that the preamble power ramping counterremains unchanged when more than half of uplink transmitting beams arechanged compared to the actually used uplink transmitting beams in theprevious random access attempt; otherwise, the preamble power rampingcounter is increased by 1. For example, in the previous random accessattempt, for a certain downlink transmitting beam, the UE transmits X(X=3) preambles and uses 3 uplink transmitting beams, for example, twobeam 1 and one beam 2; however, in the current random access attempt,for the same downlink transmitting beam, the UE transmits Y (Y=4)preambles and uses 4 uplink transmitting beams. If there are one beam 1,one beam 2, one beam 3 and one beam 4 at this time, it is indicated thattwo beams are changed. In this case, if the rule is that the preamblepower ramping counter remains unchanged when the number of changed beamsexceeds └Y/2┘=2, since 2=2, the UE needs to increase the preamble powerramping counter by 1.

b. The UE determines independent preamble power ramping counters for thetransmission of all transmitted preambles.

i. For example, in the same random access process, if at most N*Mpreambles may be transmitted in one random access attempt, each preambletransmission has its own preamble power ramping counter.

1. When the random access channel used by this preamble has passed LBT,that is, the LBT is successful, and when the uplink transmitting beamfor transmitting this preamble is changed, the preamble power rampingcounter remains unchanged; otherwise

a) when the is successful, and when the uplink transmitting beam fortransmitting this preamble remains unchanged, the preamble power rampingcounter is increased by 1; or,

b) when the LBT is failed, the preamble power ramping counter isincreased by 1.

2. When no RAR has been received before the transmission of thispreamble and when the uplink transmitting beam for transmitting thispreamble is changed, the preamble power ramping counter remainsunchanged; otherwise

a) when no RAR has been received before the transmission of thispreamble and when the uplink transmitting beam for transmitting thispreamble remains unchanged, the preamble power ramping counter isincreased by 1; or,

b) when an RAR has been received before the transmission of thispreamble, the preamble power ramping counter is increased by 1.

c). In one random access process, the UE uses only one preamble powerramping counter for the transmission of all preambles.

i. For example, in the same random access process, in one random accessattempt, total X preambles are actually transmitted, and X uplinktransmitting beams are used. When the UE performs a new random accessattempt, total Y preambles will be transmitted, and Y uplinktransmitting beams will be used.

1. When Y=X, and when less than and/or equal to 1, or Y, or Y/x, or X,or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐ uplink beams among the Yuplink beams are changed compared to the X uplink beams, the preamblepower ramping counter remains unchanged; otherwise, the preamble powerramping counter is increased by 1, where the x represents a ratio. Forexample, if x=2, X/x indicates that the preamble power ramping counterremains unchanged when more than half of the uplink transmitting beamsare changed; otherwise, the preamble power ramping counter is increasedby 1. For example, in the previous random access attempt, the UEtransmits X (X=3) preambles and uses 3 uplink transmitting beams, forexample, two beam 1 and one beam 2; however, in the current randomaccess attempt, the UE also transmits Y (Y=3) preambles and also uses 3uplink transmitting beams. If there are one beam 1, one beam 2 and onebeam3 at this time, it is indicated that only one beam is changed. Inthis case, if the rule is that the preamble power ramping counterremains unchanged if the number of changed beams exceeds └X/2┘=2, since1<2, the UE needs to increase the preamble power ramping counter by 1.

2. When Y<X, and when less than and/or equal to 1, or Y, or Y/x, or X,or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐ uplink beams among the Yuplink beams are changed compared to the X uplink beams, the preamblepower ramping counter remains unchanged; otherwise, the preamble powerramping counter is increased by 1, where the x represents a ratio. Forexample, if x=2, X/x indicates that the preamble power ramping counterremains unchanged when more than half of uplink transmitting beams arechanged compared to the actually used uplink transmitting beams in theprevious random access attempt; otherwise, the preamble power rampingcounter is increased by 1. For example, in the previous random accessattempt, the UE transmits X (X=3) preambles and uses 3 uplinktransmitting beams, for example, two beam 1 and one beam 2; however, inthe current random access attempt, the UE transmits Y (Y=2) preamblesand uses 2 uplink transmitting beams. If there are one beam 1 and onebeam 2 at this time, it is indicated that zero beam is changed. In thiscase, if the rule is that the preamble power ramping counter remainsunchanged when the number of changed beams exceeds └Y/2┘=1, since 0<1,the UE needs to increase the preamble power ramping counter by 1. Ifthere are one beam 3 and one beam 4 at this time, it is indicated thattwo beams are changed. In this case, if the rule is that the preamblepower ramping counter remains unchanged when the number of changed beamsexceeds └Y/2┘=1, since 2>1, the UE needs to remain the preamble powerramping counter unchanged.

3. When Y>X, and when less than and/or equal to 1, or Y, or Y/x, or X,or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐ uplink beams among the Yuplink beams are changed compared to the X uplink beams, the preamblepower ramping counter remains unchanged; otherwise, the preamble powerramping counter is increased by 1, where the x represents a ratio. Forexample, if x=2, X/x indicates that the preamble power ramping counterremains unchanged when more than half of uplink transmitting beams arechanged compared to the actually used uplink transmitting beams in theprevious random access attempt; otherwise, the preamble power rampingcounter is increased by 1. For example, in the previous random accessattempt, the UE transmits X (X=3) preambles and uses 3 uplinktransmitting beams, for example, two beam 1 and one beam 2; however, inthe current random access attempt, the UE transmits Y (Y=4) preamblesand uses 4 uplink transmitting beams. if there are one beam 1, one beam2, one beam 3 and one beam 4 at this time, it is indicated that twobeams are changed. In this case, if the rule is that the preamble powerramping counter remains unchanged if the number of changed beams exceedssince └Y/2┘=2, since 2=2, the UE needs to increase the preamble powerramping counter by 1.

4. Determining a specific power control mode:

a. The UE performs power control based on each of the selected downlinktransmitting beams. That is, during the transmission of M possiblepreambles corresponding to each of the selected downlink transmittingbeams, the transmitting power is calculated by using a Path Loss (PL)obtained by a same corresponding downlink transmitting beam.

b. The UE calculates the transmitting power based on a unified PL,specifically:

i. the PL corresponding to the downlink transmitting beam having themaximum Reference Signal Received Power (RSRP) is selected;

ii. the PL corresponding to the downlink transmitting beam having theminimum RSRP is selected;

iii. an average of PLs corresponding to all downlink transmitting beamsis selected; and

iv. in accordance with a predefined or configured RSRP threshold, thedownlink transmitting beam having a PL not greater than or not less thanthe threshold is randomly selected with equal probability, and thetransmitting power is calculated by using the PL of this downlinktransmitting beam.

5. The user equipment determining the maximum number of transmissions.

a. If the preamble_max configured by the base station is in the randomaccess based on the transmission of a single preamble, the UE regardsthe preamble_max as the maximum number of random access attempts, andonly one preamble may be transmitted in each attempt; or, the UEdirectly regards the preamble_max as the maximum number of preamblesthat may be transmitted by the UE in one random access process.

b. If the preamble_max configured by the base station is in the randomaccess based on the transmission of multiple preambles, the UE regardsthe preamble_max as the maximum number of random access attempts, and atmost N*M preambles may be transmitted in each attempt; or, the UEdirectly regards the preamble_max as the maximum number of preamblesthat may be transmitted by the UE in one random access process. In thiscase, the UE uses preamble_max_new=preamble_max*N*M. After one failedrandom access attempt, the UE increases the preamble transmissioncounter by X, where the X represents the number of preambles actuallytransmitted by the UE in this failed random access attempt. When thepreamble transmission counter exceeds the preamble_max_new, the UEreports a random access problem to the higher layer. Or, the UE starts arandom access timer when it begins to transmit the first preamble. Whenthe random access timer expires, the UE reports a random access problemto the higher layer. Or, the UE simultaneously maintains the preambletransmission counter and the random access timer. If the counter exceedsa limit while the timer does not expire, the UE reports a random accessproblem to the higher layer; and, if the counter does not exceed thelimit while the timer expires, the UE also reports a random accessproblem to the higher layer

6. The UE receiving a Random Access Response (RAR) message.

a. The UE stops searching when detecting a matched RAR, then reads anuplink grant in the RAR and begins to prepare for subsequent uplinktransmission.

b. When the UE detects an RAR, the UE may continuously search within aconfigured RAR window. If multiple matched RARs are found,

i. the UE randomly selects an RAR with equal probability;

ii. the UE selects, according to the uplink grant, an RAR supporting theearliest subsequent uplink transmission; and

iii. the UE determines an RAR according to an HARQ progress ID indicatedin the RAR, specifically:

1) if there are multiple different HARQ progress IDs, the user transmitscorresponding uplink data according to the uplink grant indicated in thecorresponding RAR; and

2) for a same HARQ progress ID, the UE randomly selects an RAR withequal probability, or the UE selects, according to the uplink grant, anRAR supporting the earliest subsequent uplink transmission.

Another embodiment of the random access method according to the presentdisclosure will be described below. The random access method provided inthis embodiment includes the following steps:

step 1: determining, by a User Equipment (UE), random access resources;

step 2: when it is determined according to the random access resourcesthat multiple preambles based random access is performed, determining,according to a determined number of downlink transmitting beams and anumber of preambles that may be transmitted by each downlinktransmitting beam, the maximum number of preambles that may betransmitted in one random access attempt;

step 3: determining, according to one or more determined downlinktransmitting beams, a preamble power ramping counter and a preambletransmission counter; and

step 4: performing, according to the maximum number of preambles thatmay be transmitted, the counting result of the preamble power rampingcounter and the counting result of the preamble transmitting counter,the multiple preambles based random access.

It may be known from the above that, in this embodiment, the userequipment may determine the downlink beams and the maximum number ofpreambles that may be transmitted in one random access attempt, andperform random access power control, so that the multiple preamblesbased random access may be realized.

In applications, the method further includes the step of:

selecting one preamble sequence for each of the determined downlinktransmitting beams, and transmitting preambles corresponding to thedownlink transmitting beam by this preamble sequence; or,

selecting one preamble sequence, and transmitting all preambles in onerandom access attempt by this preamble sequence; or,

selecting preamble sequences configured in the random access resources.

In applications, the method further includes the step of:

determining uplink transmitting beams for multiple preamblescorresponding to the first downlink transmitting beam, and determining,according to uplink transmitting beams, the uplink transmitting beam forthe multiple preambles corresponding to other downlink transmittingbeam; or,

randomly determining the uplink transmitting beams used by the preamblescorresponding to all downlink transmitting beams with equal probability.

In applications, the step of determining the preamble power rampingcounter includes:

determining one preamble power ramping counter for each of the selecteddownlink transmitting beams, wherein multiple preambles corresponding tothe same downlink transmitting beam share the same preamble powerramping counter; or,

determining one preamble power ramping counter for each of the selectedpreambles; or,

using only one preamble power counter by the transmission of allpreambles in one random access process.

In applications, when the UE has N determined downlink transmittingbeams and each of the downlink transmitting beams corresponds to Mpreambles,

in a case where the multiple preambles corresponding to each of thedownlink transmitting beams share a same preamble power ramping counter,when the UE performs a new random access attempt during a same randomaccess process, the method for determining the counting result of thepreamble power ramping counter includes:

for a same downlink transmitting beam, when less than and/or equal to 1,or Y, or Y/x, or X, or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐uplink beams among the actually used Y uplink beams are changed comparedto the X actually used uplink transmitting beams in the previous randomaccess attempt, the preamble power ramping counter is increased by 1;otherwise, the preamble power ramping counter remains unchanged;

in a case where one preamble power ramping counter is determined foreach of the selected preambles, the method for determining the countingresult of the preamble power ramping counter includes:

when the uplink transmitting beam for transmitting the preamble ischanged, the preamble power ramping counter remains unchanged;otherwise, the preamble power ramping counter is increased by 1;

in a case where only one preamble power ramping counter is used by thetransmission of all preambles, the method for determining the countingresult of the preamble power ramping counter includes:

during a new random access attempt, when less than and/or equal to 1, orY, or Y/x, or X, or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐ uplinkbeams among all the actually used Y uplink beams are changed compared toall the X actually used uplink transmitting beams in the previous randomaccess attempt, the preamble power ramping counter is increased by 1;otherwise, the preamble power ramping counter remains unchanged;

where the M, N, X and Y are all positive integers, and the x is a ratio.

In applications, the method further includes the step of:

during the transmission of the multiple preambles corresponding to eachof the selected downlink transmitting beams, calculating thetransmitting power by using a Path Loss (PL) obtained by a samecorresponding downlink transmitting beam; or,

calculating the transmitting power based on a unified PL.

In applications, the step of calculating the transmitting power based ona unified PL includes:

selecting the PL corresponding to the downlink transmitting beam havingthe maximum Reference Signal Received Power (RSRP); or,

selecting the PL corresponding to the downlink transmitting beam havingthe minimum RSRP; or,

selecting an average of PLs corresponding to all downlink transmittingbeams; or,

randomly selecting, according to a predefined or configured RSRPthreshold, the downlink transmitting beam having a PL not greater thanor not less than the threshold with equal probability, and calculatingthe transmitting power by using the PL of the downlink transmittingbeam.

In applications, the method for determining the counting result of thepreamble transmission counter includes:

when the preamble_max in the random access resources is determined asthe maximum number of random access attempts, whenever the UE performs arandom access attempt, increasing the preamble transmission counter by1; or,

determining, according to the preamble_max in the random accessresources, the maximum number of preamble_max_new of preambles that maybe transmitted by the UE, and increasing the preamble transmissioncounter by L if there are L preambles to be transmitted by the UE in onerandom access attempt.

Still another embodiment of the random access method according to thepresent disclosure will be described below with reference to FIG. 24. Asshown in FIG. 24, the random access method provided in this embodimentincludes the following steps:

step 901: determining, by a User Equipment (UE), random accessresources; and

step 902: determining a preamble sequence and an uplink transmittingbeam for transmitting multiple preambles to perform multiple preamblesbased random access, when it is determined according to the randomaccess resources that multiple preambles based random access isperformed.

It may be known from the above that, in the present disclosure, the apreamble sequence and an uplink transmitting beam for transmittingmultiple preambles may be determined, so that the random access tomultiple preambles may be realized.

In applications, the method further includes the step of:

determining, according to a determined number of downlink transmittingbeams and a number of preambles that may be transmitted by each downlinktransmitting beam, a preamble power ramping counter and/or a preambletransmission counter; and

the step of performing multiple preambles based random access includes:

performing the multiple preambles based random access according to thedetermined preamble sequence and uplink transmitting beam fortransmitting the multiple preambles and at least one of the followings:a counting result of the preamble power ramping counter and a countingresult of the preamble transmission counter.

In applications,

The method for determining preamble sequence for transmitting multiplepreambles includes:

selecting one preamble sequence for each of the determined downlinktransmitting beams, and transmitting the preamble corresponding to thedownlink transmitting beam by using the selected preamble sequence; or,

selecting one preamble sequence, and transmitting all preambles in onerandom access attempt by using the selected preamble sequence; or,

determining a preamble sequence configured in the random accessresources as the preamble sequence for transmitting the multiplepreambles.

In applications,

the method for determining the uplink transmitting beam for transmittingthe multiple preambles includes:

determining the uplink transmitting beam for the multiple preamblescorresponding to one downlink transmitting beam, and determining,according to the determined uplink transmitting beams, the uplinktransmitting beam for the multiple preambles corresponding to otherdownlink transmitting beam; or,

randomly determining the uplink transmitting beams used by the preamblescorresponding to all downlink transmitting beams with equal probability.

In applications, the step of determining the preamble power rampingcounter includes:

determining one preamble power ramping counter for each of thedetermined downlink transmitting beams, wherein multiple preamblescorresponding to the same downlink transmitting beam share the samepreamble power ramping counter; or,

determining one preamble power ramping counter for each preambledetermined to be transmitted; or,

determining one preamble power ramping counter for all preamblesdetermined to be transmitted.

In applications, when the UE has N determined downlink transmittingbeams and each of the downlink transmitting beams corresponds to Mpreambles,

in a case where the multiple preambles corresponding to each of thedownlink transmitting beams share a same preamble power ramping counter,when the UE performs a new random access attempt during a same randomaccess process, the method for determining the counting result of thepreamble power ramping counter includes:

for a same downlink transmitting beam, when less than and/or equal to 1,or Y, or Y/x, or X, or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐uplink beams among the actually used Y uplink beams are changed comparedto the X actually used uplink transmitting beams in the previous randomaccess attempt, the preamble power ramping counter is increased by 1;otherwise, the preamble power ramping counter remains unchanged;

in a case where one preamble power ramping counter is determined foreach preamble determined to be transmitted, the method for determiningthe counting result of the preamble power ramping counter includes:

when the uplink transmitting beam for transmitting the preamble ischanged, the preamble power ramping counter remains unchanged;otherwise, the preamble power ramping counter is increased by 1;

in a case where one preamble power ramping counter is determined for allpreambles determined to be transmitted, the method for determining thecounting result of the preamble power ramping counter includes:

during a new random access attempt, when less than and/or equal to 1, orY, or Y/x, or X, or X/x, or └X/x┘, or ┌X/x┐, or └Y/x┘, or ┌Y/x┐ uplinkbeams among all the actually used Y uplink beams are changed compared toall the X actually used uplink transmitting beams in the previous randomaccess attempt, the preamble power ramping counter is increased by 1;otherwise, the preamble power ramping counter remains unchanged;

where the M, N, X and Y are all positive integers, and the x is a setratio.

In applications, the method further includes the step of:

during the transmission of the multiple preambles corresponding to eachof the determined downlink transmitting beams, calculating thetransmitting power by using a Path Loss (PL) obtained by a samecorresponding downlink transmitting beam; or,

calculating the transmitting power based on a unified PL.

In applications, the step of calculating the transmitting power based ona unified PL includes:

selecting the PL corresponding to the downlink transmitting beam havingthe maximum Reference Signal Received Power (RSRP); or,

selecting the PL corresponding to the downlink transmitting beam havingthe minimum RSRP; or,

selecting an average of PLs corresponding to all downlink transmittingbeams; or,

randomly cling, according to a predefined or configured RSRP threshold,the downlink transmitting beam having a PL not greater than or not lessthan the threshold with equal probability, and calculating thetransmitting power by using the PL of the downlink transmitting beam.

In applications, the method for determining the counting result of thepreamble transmission counter includes:

whenever the UE performs a new random access attempt, increasing thepreamble transmission counter by 1; or,

whenever the UE performs a new random access attempt and there are Lpreambles determined to be transmitted in the new random access attempt,increasing the preamble transmission counter by L, where the L is apositive integer.

In applications, the method further includes the step of:

when the preamble transmission counter exceeds a preset preamble maximumpreamble_max, reporting a random access problem; or,

when the preamble transmission counter exceeds preamble_max*N*M,reporting a random access problem, where N is the number of thedetermined downlink transmitting beams, M is the number of preamblescorresponding to each of the downlink transmitting beams, and both M andN are positive integers. The reporting a random access problem isreporting a random access problem to the higher layer.

In applications, the method further includes the step of:

starting a random access timer when the UE starts to transmit a firstpreamble, and reporting a random access problem when the random accesstimer expires; or,

reporting a random access problem when the preamble transmission counterexceeds the preset preamble maximum preamble_max or preamble_max*N*M andwhen the random access timer does not expire; or,

reporting a random access problem when the preamble transmission counterdoes not exceed the preset preamble maximum preamble_max orpreamble_max*N*M and when the random access timer expires;

where N is the number of the determined downlink transmitting beams, Mis the number of preambles corresponding to ch of the downlinktransmitting beams, and both M and N are positive integers. Thereporting a random access problem reporting a random access problem tothe higher layer.

In applications, the step of performing multiple preambles based randomaccess includes:

determining a Random Access Response (RAR);

the method for determining the RAR includes:

detecting a matched RAR; or

detecting an RAR, continuously searching within a configured RAR searchwindow, and determining the RAR in the following way if multiple matchedRARs are found:

randomly selecting an RAR with equal probability;

selecting, according to an uplink grant, an RAR supporting the earliestsubsequent uplink transmission; and

determining an RAR according to a Hybrid Automatic Repeat reQuest (HARQ)progress ID indicated in the RAR.

In applications, the step of determining an RAR according to an HARQprogress ID indicated in the RAR includes:

if there are multiple different HARQ progress IDs, transmittingcorresponding uplink data according to an uplink grant indicated in thecorresponding RAR; or,

for a same HARQ progress ID, randomly selecting an RAR with equalprobability, or selecting, according to an uplink grant, an RARsupporting the earliest subsequent uplink transmission.

In applications, the step of determining, by a User Equipment (UE),random access resources includes:

acquiring, by the UE, measurement reference signals configured by a basestation, the measurement reference signals including a synchronizationsignal block and/or a Channel State Information-Reference Signal(CSI-RS);

measuring, by the UE, the configured measurement reference signals toobtain a measurement result of the measurement reference signals,reporting the measurement result, and acquiring random access resourcesconfigured according to the measurement result by the base station.

In applications, the step of reporting the measurement result includesany one of the following:

feeding back measurement results of all the configured measurementreference signals to the base station;

feeding back, according to a predefined or configured threshold and tothe base station, measurement results of all measurement referencesignals greater than or not less than the threshold; and

feeding back measurement results of all the configured measurementreference signals to the base station, and feeding back, according topredefined or configured threshold and to the base station, indexes ofall measurement reference signals greater than or not less than thethreshold.

In applications, the step of determining, by a UE, random accessresources includes:

reading, by the UE and from random access configuration informationtransmitted in a downlink channel by a base station, available randomaccess resources in the local cell; and

selecting, according to the measurement result of the measurementreference signals, indexes of the measurement reference signals toobtain corresponding random access resources.

In applications, the step of selecting, according to the measurementresult of the measurement reference signals, indexes of the measurementreference signals includes:

selecting indexes of multiple measurement reference signals having theoptimal measurement result;

selecting, based on a preset or configured threshold, indexes of allmeasurement reference signals having a measurement result satisfying thethreshold;

selecting, based on a preset or configured threshold, indexes ofmultiple measurement reference signals from the indexes of allmeasurement reference signals having a measurement result satisfying thethreshold.

In applications, the method further includes the step of:

attempting to receive a signal on a channel, on which signals are to betransmitted, within a period of time before the real transmission ofsignals, indicating that this channel has been occupied if the receivedsignal energy is not less than a preset or configured threshold, andgiving up this transmission.

An embodiment of a user equipment according to the present disclosurewill be described below with reference to FIG. 25.

An acquisition unit 1001 is configured to determine random accessresources.

A random access unit 1002 is configured to, when it is determinedaccording to the random access resources that multiple preambles basedrandom access is performed, determine a preamble sequence and an uplinktransmitting beam for transmitting multiple preambles and performmultiple preambles based random access.

In one aspect, the present disclosure further provides a random accessmethod, including steps of:

configuring, by a base station, random access resources; and

transmitting the random access resources, the random access resourcesbeing used for performing multiple preambles based random access by aUser Equipment (UE).

In another aspect, the present disclosure further provides a basestation, including:

a configuration unit configured to configure random access resources;and

a transmission unit configured to transmit the random access resources,the random access resources being used for performing multiple preamblesbased random access by a User Equipment (UE).

In conclusion, in the present disclosure, a User Equipment (UE)determines random access resources; and, when it is determined accordingto the random access resources that multiple preambles based randomaccess is performed, the maximum number of preambles that may betransmitted in one random access attempt and the preamble sequences anddownlink transmitting beams for the preambles that may be transmittedare determined according to the determined number of downlinktransmitting beams and the number of preambles that may be transmittedeach downlink transmitting beam, and the multiple preambles based randomaccess is then performed. In the present disclosure, the UE maydetermine the a preamble sequence and an uplink transmitting beam fortransmitting multiple preambles, so that the present disclosure mayrealize the random access to multiple preambles.

In addition, the functional units in the embodiments of the presentdisclosure may be integrated into one processing module; or, each unitmay exist alone physically; or, two or the like units may be integratedinto one module. The integrated module may be implemented in the form ofhardware, or may be implemented in the form of a software functionalmodule. If the integrated module is implemented in the form of asoftware functional module and sold or used as an independent product,the integrated module may also be stored in a computer-readable storagemedium.

The storage medium mentioned above may be a read-only memory, a magneticdisk, an optical disk, etc.

The procedure described in the specification, claims and the aboveaccompanying drawing of the present invention contains a multiple ofoperations presented in a specific order. However, it shall clearlyunderstand that, these operations can be executed or executed inparallel in a different order compared with the order presented in thepresent invention. The operation numbers such as 101, 102 or others aremerely used for distinguishing each different operation. The operationnumbers themselves does not represent any execution order. In addition,these procedures can include more or less operations, which can beexecuted or executed in parallel in an order. It is to be noted that,the descriptions “the first”, “the second” and or others descriptions inthe present invention are used for distinguishing the differentinformation, devices, modules or others, which do not represent anysequential order, and do not limit “the first” and “the second” aredifferent types.

The technical scheme in the embodiments of the present invention will befurther described clearly and completely in combination with theaccompanying drawings in the embodiments of the present invention below.Apparently, the described embodiments are merely parts of theembodiments of the present invention, not all the embodiments. Based onthe embodiments of the present disclosure, all the other embodimentsacquired by those skilled in the art without paying out any inventivework belong to the protection scope of the present invention.

The procedure of transmitting beam failure recovery request according tothe disclosure is as illustrated in FIG. 27, specifically, comprisingthe following steps of:

acquiring, by a terminal, channel time-frequency resource configurationinformation and preamble configuration information used for transmittinga beam failure recovery request;

selecting, by the terminal, a candidate downlink transmit beam accordingto a measurement result;

selecting, by the terminal, a channel time-frequency resource and/or apreamble according to association between a downlink transmit beam andthe channel time-frequency resource and/or the preamble, thetime-frequency resource configuration information and the preambleallocation information; and

transmitting, by the terminal, the preamble on the channeltime-frequency resource.

In another embodiment, a resource allocation manner for a beam failurerecovery request will be introduced in combination with a specificsystem. Assuming that the base station operates in a high frequency bandand multi-beam operation is used to compensate for large path loss. Thebeam failure recovery request uses a dedicated time-frequency resourceand a sequence resource. The time-frequency resource is similar to arandom access channel time-frequency resource, and can be distinguishedfrom the random access channel time-frequency resource by using afrequency division multiplexing manner or a time division multiplexingmanner, and the like.

The base station uses a high layer signaling or downlink controlinformation to configure resources for the beam failure recoveryrequest. The resources include a time-frequency resource and a sequenceresource. First, the sequence resource allocation manner provided inthis embodiment will be described. A beam failure recovery request mayuse a same sequence resource pool as a random access procedure. Forexample, the preamble resource pool used by a random access procedurecontains Npre preambles, and the beam failure recovery request uses thesame preamble resource pool. Assuming that the dedicated time-frequencyresource used for each beam failure recovery request has associationwith M downlink transmit beams. In this case, the number of terminalscapable of transmitting the beam failure recovery request at the sametime can be supported on the dedicated time-frequency resource is└N_(pre)/M┘. In order to configure a preamble resource for a beamfailure recovery request to a terminal in a serving cell, the possibleallocations are as follows:

a. ┌log₂ M┐ bits are used to configure the number of the preamble groupson a same time-frequency resource, which decides the number of beamscorresponding to the same time-frequency resource. ┌log₂(└N_(pre)/M┘)┐bits are used to inform the terminal of which preamble in a group beingused to perform the beam failure recovery request. The specific groupingmanners are specifically described as below:

a.1. Consecutive └N_(pre)/M┘ preambles are divided into one group whichcorresponds to one beam on the dedicated time-frequency resource.Wherein, └N_(pre)/M┘ preambles included in each group are allocated todifferent terminals for use. Take N_pre=64, M=8 as an example, that is,assuming that the maximum number of beams corresponds to a sametime-frequency resource is 8. The preambles on a same time-frequencyresource is divided into eight groups, and consecutive eight preamblesare divided into one group, so as to correspond to one downlink transmitbeam. Eight preambles in each group can be allocated to differentterminals, that is, it can be supported that eight terminals transmitthe beam failure recovery request on a same time-frequency resource. Theallocation manner is as shown in FIG. 28.

That is, each group includes the same number of preambles and indexesthe preambles in each group, and preambles with the same index indifferent groups are allocated to the same terminal. After the preamblesare grouped, a one-to-one correspondence between the groups based ongrouping number and the groups based on beam indexes (for example, aCSI-RS index or a beam RS index) for different groups is established.This correspondence is pre-notified or pre-determined as a pre-definedrule. It needs to configure the following parameters:

three bits for indicating the actual number of groups;

three bits for indicating the allocation situation of preambles in eachgroup.

Specifically, in the above-described embodiment, three bits are used tonotify the actual number of groups to the terminal and another threebits are used to notify the indexes in groups, and the notificationformat as shown in FIG. 29.

For the example shown in FIG. 28, a group indication is (111)2,indicating that the preamble sets are divided into eight groups, andeight preambles are contained in each group. The preamble correspondingto each beam is determined by an index indication within group. For theconfiguration information that the index indication within group is n,the preamble indexes

corresponding to different beams used by the terminal are: n, n+M, . . .,

$n + {\left( {\left\lfloor \frac{N_{pre}}{M} \right\rfloor - 1} \right){M.}}$For example, for the example shown in FIG. 28, if the index indicationwithin group is n=1, according to the above manner, the preamble indexescorresponding to different beams respectively are 1, 9, . . . , 57.

a.2. Adjacent └N_(pre)/M┘ preambles are divided into one group whichcorresponds to one downlink beam. Consecutive └N_(pre)/M┘ preambles areallocated to one terminal for a transmit beam failure recovery request.FIG. 5 shows a simple example of this method.

In the example shown in FIG. 30, assuming that N_pre=64, M=8, for thismanner, the above-described preamble configuration indication manner canstill be used, that is, the preamble configuration indication includes agroup indication and an in-group index indication. Different from theabove-described manner, the group indication in this manner is used toindicate an interval between two adjacent preamble indexes in the group,and the index in the group is used to indicate the preamble indexallocated to the terminal in the group. Specifically, if the groupindication is m and the index within a group is n, then the preambleindexes allocated to the terminal in sequence are: mn, mn+1, . . . ,mn+M−1. Still taking the example shown in FIG. 29 as an example, thegroup indication is (111)2, that is, the interval between two adjacentpreamble indexes in the preamble group corresponding to the samedownlink transmit beam is by 7+1=8. If the index in the group is 1, thepreamble indexes for the terminal are: 8, 9, . . . , 15.

The correspondence between the preamble and the downlink transmit beamis fixed in this manner, and a certain of flexibility is damaged whilethe signaling overhead is small.

b. When configuring preambles, the first preamble index and the numberof the preambles allocated to the terminal are notified. While, thecorrespondence between the preambles and the downlink transmit beams canbe determined in a predetermined manner. For example, the number ofpreambles included in the notification represents the number of downlinktransmit beams corresponding to the time-frequency resource, and theterminal sorts the downlink transmit beams corresponding to thetime-frequency resource based on beam index (or a CSI-RS index, a beamRS index, or a beam ID index or the like) and establishes one-to-onecorrespondence between the downlink transmit beams and the index-sortedpreambles.

Another manner is to show a notification and indicate the downlink beamcorresponding to the preamble. Wherein, the downlink beam can beindicated by a beam ID, a CSI-RS index, a downlink synchronization blockindex and a beam RS index. A beam index vector with the same length asthat of the available preambles is notified, while a preamble index isnotified, for establishing beam indexes which correspond to thepreambles one by one.

Still taking that eight downlink transmit beams corresponding to eachdedicated time-frequency resource as an example, the indicationinformation format is as shown in FIG. 31 when the preamble resourcesare allocated.

A simple example is that if the preamble start index is 8 and thepreamble number is 8, then the allocated preamble index is 8, 9, 10, 11,12, 13, 14, 15, respectively, corresponding to the downlink beams 1-8.It should be noted that the downlink beam index is characterized by adownlink signal index, including a downlink synchronization block index,a CSI-RS index, a beam ID, or a beam RS index.

An allocation manner of time-frequency resources will be described belowbriefly. For the dedicated time-frequency resource for the beam failurerecovery request that is frequency-division multiplexed with a randomaccess channels, the dedicated time-frequency resource may be allocatedusing the frequency offset and the channel indication index.

Specifically, since the dedicated time-frequency resources and therandom access channel coexist in a frequency division multiplexingmanner, the dedicated time-frequency resource may use a random accesschannel configuration to determine a time-frequency resource structureand determine the frequency location of the dedicated time-frequencyresource by the frequency offset. Wherein, the frequency offset ischaracterized by the number of physical resource blocks. At the sametime, considering that there are multiple available random accesschannels in one time unit (such as one radio frame), multiple randomaccess channels may also exist in the frequency domain. The adopteddedicated channel time-frequency resources are notified to the terminalby the channel indication index.

At the same time, the base station configures the downlink transmit beamindex set corresponding to the dedicated time-frequency resource. Thedownlink transmit beam index may be characterized by a downlinksynchronization signal block index, a CSI-RS index, a beam ID, or a beamRS index.

For more candidate downlink transmit beams, and multiple dedicatedtime-frequency resources are needed to complete the associated of alldownlink transmit beams, when a dedicated time-frequency resource forbeam failure recovery is configured, multiple time-frequency resourceindication indexes may be configured and associated downlink transmitbeam index sets are configured respectively.

To further increase the number of terminals that can be supported, theperiod of the dedicated time-frequency resource or the availablesubframes/radio frames may be further configured. For example, onepossible manner is that the configuration information carries theavailable subframe configuration and is notified by way of an indextable. Table 9 shows a possible index table.

TABLE 9 Available subframe index Index Available subframe index 0 all 1odd subframe 2 even subframe 3 subframe 0 4 subframe 1 . . . . . .

In a similar manner, the available radio frame can be configured. Table10 shows a possible index table.

TABLE 10 Available radio frame index Index Available radio frame index 0all 1 odd radio frame 2 even radio frame . . . . . .

When carrying an available subframe/radio frame index, the dedicatedchannel time-frequency resource configuration consists of the followingparts: a frequency offset, a channel indication index, a downlink beamindex, an available subframe index and an available radio frame index.

The time-frequency resource for beam failure recovery request can alsoconfigured by a manner of resource allocation. In this case, theabove-described frequency offset and channel indication index in theconfiguration information need to be replaced by the resourceconfiguration information. While the downlink beam index is still usedto indicate the downlink beam corresponding to the time-frequencyresource. The period of the dedicated channel time-frequency resourcecan be configured by available subframe indexes and available radioframe indexes.

The behavior of the terminal side is briefly described as follows:

The terminal reads dedicated channel time-frequency resourceconfiguration information and preamble configuration information, tolearn a following correspondence between a downlink transmit beam and atime-frequency resource/a preamble.

The terminal acquire an optimum downlink transmit beam according to adownlink measurement result when needing to initiate a beam failurerecovery request, and determine the time-frequency resource and thepreamble for transmitting the beam failure recovery request according tothe correspondence between the downlink transmit beam and thetime-frequency resource and/or the preamble.

The selected preamble is transmitted on the selected time-frequencyresource.

In another embodiment, a beam failure recovery procedure will beintroduced in combination with a specific system. In this embodiment,the beam failure recovery procedure is briefly described as follows:

A terminal reads a dedicated time-frequency resource and a preambleresource for a beam failure recovery procedure.

The terminal determines to select a downlink candidate beam according toa downlink measurement result and select a time-frequency resource and apreamble according to association between the downlink transmit beam andthe time-frequency resource/the preamble, if the terminal needs totransmit a beam failure recovery request. The terminal chooses to fallback to a contention-based random access procedure, if the terminalcannot select the associated time-frequency resource/preamble (forexample, the downlink transmit beam is not in the correspondence list)according to the downlink candidate beam selected according to themeasurement result.

The terminal transmits the preamble on the dedicated channeltime-frequency resource.

The request is considered as failed, if no response is detected in thecorresponding detection window after the preamble transmitted on thededicated channel time-frequency resource, and then the transmittingpower of the preamble is increased according to a pre-defined powerclimb interval, and the beam failure recovery request is retransmitted.

The procedure of contention-free beam failure recovery request isconsidered as failed, and falls back to the contention-based randomaccess procedure, if the times of transmitting the beam fail recoveryrequest exceeds the available maximum transmitting times.

According to the above-described procedure, the beam failure recoveryrequest information is needed to be carried in message 3, if theprocedure falls back to the contention-based random access procedure.Specifically, under this triggering condition, the information carriedin message 3 includes:

terminal identification (e.g., C-RNTI already allocated by a basestation)

beam failure recovery request indication

candidate downlink beam index

other information

Wherein, the terminal identification is used by a base station todistinguish the terminal that initiates a beam failure recovery request;the beam failure recovery request indication is used to notify the basestation that the random access procedure is used to initiate a beamfailure recovery request; and the candidate downlink beam index is usedto notify the base station the candidate downlink transmit beam expectedby the terminal in the beam failure recovery procedure. The index may becharacterized by a variable, such as a downlink synchronization blockindex, a CSI-RS index, a beam ID or a beam RS index, capable ofdescribing a downlink transmit beam. In addition, it should be notedthat the candidate downlink beam index carried in message 3 may indicateone or more downlink transmit beams. For example, the candidate downlinkbeam index may correspond to a single downlink transmit beam or maycorrespond to multiple downlink transmit beams (downlink transmit beamgroup). Another possible manner is to carry multiple candidate beamindexes in message 3, used for notifying the base station the candidatebeam index set.

In this case, message 4 carries a response of the beam failure recoveryrequest, that is, message 4 carries the terminal indication and theresponse of the beam failure recovery request.

In another embodiment, a request manner of on demand system informationwill be introduced in combination with a specific system. In thisembodiment, the procedure of acquiring, by a terminal, on demand systeminformation is as follows:

A terminal selects a preamble needed to be transmitted according toassociation between on demand system information or a system informationgroup and a random access preamble;

the terminal transmits the associated preamble in a random accesschannel; and

the terminal detects a random access response in a downlink controlchannel, and acquires the time-frequency location of system information.

In this embodiment, it is assumed that the base station reserves a partof the preambles and establishes association with the correspondingsystem information or system information group. The correspondence maybe indicated by a master information block in broadcast information or asystem information block indicated by the master information block.Possible indication manners are notified by a lookup table manner. Forexample, the correspondence between the preamble index and the on demandsystem information/system information group is established by a lookuptable. Table 11 shows a possible correspondence lookup table.

TABLE 11 Possible association lookup table System information/ Preambleindex system information group 57 7 58 8 59 9 60 7, 8 61 7, 9 62 8, 9 637, 8, 9

In Table 11, the system information that needs to be transmitted usingthe manner of on demand transmission is system information 7, 8, 9 andtheir combinations. The base station reserves seven preambles (indexes57 to 63), wherein each preamble corresponds to one system informationor a combination of system information thereof.

The table may be determined in a pre-determined manner, or the on demandsystem information or system information group are notified to theterminal by using a manner of high layer signaling notification. If amanner of high layer signaling notification is adopted, the possiblemanner includes:

a. the configuration content includes: number of on demand systeminformation needed to be transmitted and the corresponding systeminformation index; and a vector, composed of 0, 1, constructed with thelength equivalent to the number of on demand system informationaccording to the number of system information, wherein 1 in the vectorindicates that the corresponding system information in the group isneeded to be transmitted, and 0 in the vector indicates that thecorresponding system information in the group does not need to betransmitted. By this vector, the correspondence between the randomaccess preamble and the on demand system information/system informationgroup are indicated.

As for the preamble, the preamble for transmitting the on demand systeminformation request is configured by configuring the first preamble andthe number of the reserved preambles. In addition, it should be notedthat the number of the preambles may indicate the number of the ondemand system information/system information groups.

Taking the example shown in Table 11 as an example, the relatedconfiguration content of the preamble is that the first preamble index57 and number 7 of the available preambles are configured. By these twoparameters, the terminal determines the preamble for requested on demandsystem information.

At the same time, number of on demand system information required to betransmitted by base station is 3, and the corresponding indexes aresystem information 7, system information 8, and system information 9,and seven groups of vectors, with a length of 3, consisting of 0 and 1are configured as follows:

(1,0,0) (0,1,0) (0,0,1) (1,1,0) (1,0,1) (0,1,1) (1,1,1)

In this manner, the configured and notified information includes: numberof preambles, start index of the preambles, number of on demand systeminformation, corresponding system information indexes, and multiplegroups of vectors consisting of 0 and 1.

In addition, it should be noted that, when configuring the preamble, itis also possible to directly configure indexes of multiple availablepreambles.

b. the configuration content includes: configuring a tuple whenconfiguring the on demand system information. This tuple includes:number of on demand system information in a group, and the correspondingsystem information index. That is, the tuple may be expressed as:

(NSI, I_(SI₁), … , I_(SI_(N_(Si)))).Where NSI is the number of system information in the tuple, and I_(SI)_(n) is the index of the nth system information.

For example, still taking the example shown in Table 9 as an example,all tuples can be expressed as:

(1,7), (1,8), (1,9), (2, 7, 8), (2, 7, 9), (2, 8, 9), (3, 7, 8, 9)

It should be noted that, in the above example, an index of systeminformation is directly used, and another configuration manner with alower overhead is to first configure on demand system information thatneeds to be transmitted, that is, it is indicated in a masterinformation block or Remaining Minimum System Information (RMSI)indicated by the master information block. Actual system informationindex is replaced by the corresponding relative index in the tuple.

Still taking the above example as an example, when the on demand systeminformation configured in the master information block or the RMSIindicated by the master information block is the system information 7, 8and 9, the foregoing tuple may be expressed as:

(1,0), (1,1), (1,2), (2, 0, 1), (2, 0, 2), (2, 1, 2), (3, 0, 1, 2)

Wherein, index 0 indicates system information 7, index 1 indicatessystem information 8, and index 2 indicates system information 9.

The configuration and notification of the preamble can be configured asdescribed above.

In another method, a preamble index is also included in the tuple. Inthis case, the preamble no longer needs to be separately configured. Forexample, the tuple can be expressed as (I_(p), N_(SI), I_(SI) ₁ , . . ., I_(SI) _(NSI) ), where Ip is a preamble index.

The terminal acquires the correspondence between the on demand systeminformation and the preamble by reading the master information block orthe RMSI indicated by the master information block. When the terminalneeds to obtain on demand system information or system informationgroup, the associated preamble is selected according to the foregoingcorrespondence and transmitted on the random access channel.

After finishing transmitting of the preamble, the terminal detects thecontrol channel in the random access response window. The random accessresponse is detected and the physical downlink shared channel indicatedin the corresponding control channel continues to be detected, if thecontrol channel is scrambled by the RA-RNTI corresponding to the randomaccess channel time-frequency resource for transmitting the preamble.The random access response is considered to be received successfully, ifthe random access response in the physical downlink shared channelcontains the preamble identifier matching the transmitted preamble.

For the random access procedure triggered by the on demand systeminformation request, the random access response at least includes:

random access preamble identifier

downlink resource allocation information

Wherein, the random access preamble identifier is used to indicate whichpreamble is transmitted corresponding to the random access response; andthe downlink resource allocation information is used to indicate theterminal to receive the time frequency resource of the requested ondemand system information.

After receiving the random access response and detecting that thepreamble identifier included in the random access response matches thetransmitted preamble, the terminal considers the on demand systeminformation request is transmitted successful. Further, the terminalreads the corresponding system information or system information groupaccording to the downlink resource allocation information in the randomaccess response.

It should be noted that if multiple terminals initiate multiple requestsof on demand system information/system information groups, the basestation transmits a maximum set of system information according to themaximum set of the system information/system information groups.Corresponding transmitting and detecting manners can be as follows:

a. the maximum set containing multiple system information uses a samerandom access response for indicating downlink resources. Wherein, thepreamble corresponding to the preamble identifier in the random accessresponse corresponds to the maximum set of the system information set.After detecting the transmitting of the random access response, if thepreamble corresponding to the preamble identifier does not match thepreamble transmitted by the terminal while the system information groupcorresponding to the preamble includes the system information requestedby the terminal, it still considers that the on demand systeminformation is requested successful, and the corresponding systeminformation is read according to the downlink resource allocationinformation therein.

b. random access responses are respectively generated according to thedetected random access preambles, while downlink resources are allocatedaccording to the maximum set of system information, that is, thedownlink resource allocation information in multiple random accessresponses may be the same or different, and the terminal reads thecorresponding system information according to the downlink resourceallocation information in the random access response.

Another manner of transmitting and detecting a random access response isas follows. The downlink control channel corresponding to the randomaccess response is scrambled by a dedicated RNTI, for example, an ondemand system information SI-RNTI (On demand SI-RNTI; OD-SI-RNTI), anddifferent on demand system information may use the same OD-SI-RNTI, thatis, adopt a uniform OD-SI-RNTI; or different system information/systeminformation groups adopt different OD-SI-RNTIs, wherein correspondencesbetween these different OD-SI-RNTIs and the corresponding systeminformation/system information groups may be notified to the terminal ina predetermined manner, or corresponding association may be notified bya high layer signaling configuration.

In addition, it should be noted that, if the second case is adopted, thebase station may allocate the OD-SI-RNTIs according to the maximum setof system information requested by the terminal and allocate associateddownlink time-frequency resources.

If the terminal detects the downlink control channel in the randomaccess response window, if the system information/system informationgroup corresponding to the OD-SI-RNTI used for scrambling the downlinkcontrol channel matches the system information request transmitted orincludes the transmitted system information, it is considered that arandom access response is detected, and the downlink physical sharedchannel indicated by the downlink control channel is further detected.

In an implementation manner, the base station transmits the systeminformation/system information group requested by the terminal on thedownlink physical shared channel, to complete the request and thetransmitting of on demand system information. In another implementationmanner, the OD-SI-RNTI-scrambled control channel indicates the locationof the time-frequency resource for the random access response, whereinthe random access response contains the following contents:

random access preamble identifier

downlink time-frequency resource allocation information

Wherein, the random access preamble identifier is used to indicate whichpreamble is transmitted corresponding to the random access response; andthe downlink resource allocation information is used to indicate theterminal to receive the time frequency resource of the requested ondemand system information.

In the above manner, the random access preamble identifier is optional.The terminal reads the corresponding system information according to thedownlink time-frequency resource allocation information.

In another embodiment, a request manner of on demand system informationwill be introduced in combination with a specific system. In thisembodiment, the master information block or the system information blockindicated in the master information block does not indicate thecorrespondence between the preamble and the on demand systeminformation, but merely indicates the on demand system informationindex.

In this case, if the terminal needs to obtain the on demand systeminformation, it needs to be done through a random access procedure. Theprocedure for the terminal to obtain the on demand system information isas follows:

the terminal transmits a random access preamble on a random accesschannel;

the terminal detects a random access response in the random accessresponse window. If the control information scrambled by the RA-RNTIcorresponding to the random access channel time-frequency resource usedin the control channel is detected, it is considered that random accessis detected; the terminal continues to detect the downlinktime-frequency resource indicated by the control channel, and the randomaccess response is considered to be received successfully, if the randomaccess response transmitted in the associated time-frequency resourcecontains the preamble identifier matching the transmitted preamble;

the terminal transmits message 3 on a designated time-frequency resourceaccording to the uplink grant carried in the random access response,wherein message 3 includes a request for transmitting the systeminformation; and

the terminal receives message 4 and confirms that the on demand systeminformation is requested successful.

Specifically, in this case, message 3 transmitted by the terminalincludes a request for transmitting on demand system information, forexample, one or more system information indexes, or an index of a systeminformation group. In addition, for the terminal in the connected state,an indication of the beam may be transmitted by the base station inmessage 3, to assist the base station to adjust the downlink transmitbeam of message 4. Wherein, the transmit beam indication may have thefollowing forms:

a. when the terminal carries the allocated C-RNTI in message 3 andcarries one bit of indication information Beam_flag in message 3, andthe indication information is 1, it indicates that the base station canuse the downlink transmit beam used for previously transmitting downlinkdata for the terminal.

b. the terminal carries the beam indication information in message 3.The information may be a synchronization signal block index, an index ofa CSI-RS, or a beam reference signal index. The terminal learns theoptimal downlink beam direction through a downlink measurement. Forexample, according to the measurement of the reference signal receivingpower for the synchronization signal block, an optimal synchronizationsignal block index is learned and transmitted to the base station bymessage 3. In another case, for measurements of each beam CSI-RS or beamreference signal, the CSI-RS index or the beam reference signal indexcorresponding to the optimal downlink beam is learned, and the CSI-RSindex or the beam reference signal index is transmitted by message 3.

c. the terminal carries the beam offset indication in message 3. Thisinformation is used to notify the base station the offset of the optimaltransmit beam direction compared with the current transmit beamdirection.

After receiving and detecting the beam indication in message 3, the basestation may select to adjust the transmit beam direction of message 4according to the beam indication or determine the transmit beamdirection of message 4 according to the scheduling situation.

For this scenario, there are several manners for transmitting anddetecting message 4:

a. The downlink control information indicating the location of message 4is scrambled by using the C-RNTI or the TC-RNTI, and the downlinktime-frequency resource scheduling information for transmitting thesystem information is transmitted in message 4, and the systeminformation index may be additionally transmitted. After receiving andsuccessfully detecting message 4, the terminal acquires thetime-frequency resource location of the corresponding system informationaccording to the downlink time-frequency resource scheduling informationof message 4 and reads the system information.

b. The corresponding downlink control information is scrambled by usingthe above OD-SI-RNTI, wherein, the OD-SI-RNTI is the same for each ondemand system information. The corresponding control informationincludes a system information index (which may include multiple systeminformation indexes) and associated downlink time-frequency resourceallocation information. Another indication manner is that only thedownlink time-frequency resource allocation information is indicated inthe associated downlink control information, and the system informationindex and the corresponding system information are transmitted in theassociated downlink time-frequency resource.

c. The associated downlink control information is scrambled by using theabove OD-SI-RNTI, wherein the OD-SI-RNTI for each on demand systeminformation/system information group is different. The associateddownlink control information includes downlink time-frequency resourceallocation information which is used to indicate the terminal to readthe location of the system information. When transmitting the systeminformation, the base station considers the maximum set of systeminformation to be transmitted, and scrambles the downlink controlinformation by using the OD-SI-RNTI corresponding to the maximum set.The terminal detects the downlink control information, if it is detectedthat the OD-SI-RNTI used for scrambling is the same as the requestedsystem information or contains the requested system information, theterminal considers that the system information request is transmittedsuccessfully and further reads system information according to thedownlink time-frequency resource allocation information in the downlinkcontrol information.

The present invention provides an apparatus for a beam recovery request,as shown in FIG. 32, comprising the following modules:

a configuration information acquisition module, configured to acquirechannel time-frequency resource configuration information and preambleconfiguration information for transmitting a beam failure recoveryrequest;

a candidate downlink transmit beam selecting module, configured toselect a candidate downlink transmit beam according to a measurementresult;

a channel time-frequency resource and preamble selecting module,configured to select a channel time-frequency resource and/or apreamble, according to the correspondence between the downlink transmitbeam and the channel time-frequency resource and/or the preamble, andthe channel time-frequency resource configuration information and thepreamble configuration information; and

a preamble transmitting module, configured to transmit the selectedpreamble on the selected channel time-frequency resource.

The present invention provides an apparatus for requesting to transmitsystem information, as shown in FIG. 33, comprising the followingmodules:

a preamble selecting module, configured to select a preamble accordingto association between on demand system information or systeminformation group and a random access preamble;

a preamble transmitting module, configured to transmit the preamble on arandom access channel; and

a random access response detecting module, configured to detect a randomaccess response and acquire a time-frequency resource location of thesystem information or system information group.

The present invention provides another apparatus for requesting totransmit system information, comprising the following modules:

a preamble transmitting module, configured to transmit a preamble on arandom access channel;

a random access response module, configured to detect a random accessresponse;

a message 3 transmitting module, configured to transmit message 3according to an uplink grant indication in the random access response,wherein message 3 comprises a system information index; and

a message 4 detecting module, configured to detect message 4 and acquirethe time-frequency resource location of the system information andsystem information group.

With reference to the above detailed disclosure of the presentdisclosure, it can be seen that, compared with the prior art, thepresent disclosure has at least the following beneficial technicaleffects:

First, the present invention provides a contention-free resourceallocation manner for beam failure recovery request, which caneffectively reduce the signaling overhead caused by resource allocation.

Second, in the beam failure recovery request method provided by thepresent invention, it can fall back to the contention-based randomaccess procedure after the request of transmitting contention-freefails, which has a certain degree of flexibility and a certain increasein the possibilities.

Third, the method for requesting to transmit on demand systeminformation provided by the present invention can reduce the signalingoverhead caused by the random access response and the transmission ofmessage 4, and reduce the delay of obtaining the system information bythe terminal.

In several embodiments provided by the present invention, it should beunderstand that, the disclosed systems, devices and methods can berealized by other modes. For example, the device embodiment describedabove is merely illustrative. For example, the classification of theunits is merely a logical function classification. Other classificationmodes can be provided while in the actual implementations. For example,a multiple of units or components can be combined or can be integratedto another system, or some features can be ignored, or are not beexecuted. On the other point, the displayed or discussed coupling,directly coupling or communication connection between each other can beindirect coupling or communication connection of devices or unitsthrough some interfaces, which can be electrical, mechanical or othermodes.

The unit as a separator for illustration can be separated physically orcannot be separated physically, the unit as a display component can be aphysical unit or cannot be a physical unit, in other word, the displayunit can located in one place, or the physical unit can be distributedto a multiple of network units. Part of units or all the units can beselected according to the actual requirement to realize the purpose ofthe embodiment.

Moreover, each of functional units in each embodiment of the presentinvention can be integrated into one procedure unit, or can exist inisolation as each unit physically, or can be integrated into one unit byat least two units. The above integrated unit can be realized usinghardware, or can be realized using software functional unit.

Those skilled in the art can understand that part of the steps or thewhole steps of the method of the embodiments can be completed by theindication of the related hardware according to the program. The programcan be stored in a computer readable storage medium. The storage mediumcan comprises: Read Only Memory (ROM), Random Access Memory (RAM), Disc,CD or other storage mediums.

A mobile terminal provided in the present invention is described indetail. For those skilled in the art, according to the idea ofembodiment of the present invention, there are changes on the specificimplementations or application scopes. In conclusion, the content of thespecification should not be understood as the limitation of the presentinvention.

The foregoing descriptions are merely some implementations of thepresent disclosure. It should be pointed out that, to a person ofordinary skill in the art, various improvements and modifications may bemade without departing from the principle of the present disclosure, andthese improvements and modifications shall be regarded as falling intothe protection scope of the present disclosure. It may be understood bya person of ordinary skill in the art that all or part of the steps invarious methods of the embodiments may be implemented by instructingrelated hardware using programs, and the programs may be stored in acomputer readable storage medium. The storage medium may include: an ROM(Read Only Memory), an RAM (Random Access Memory), a magnetic disk, anoptical disk or the like.

The methods and devices according to the specific implementation havebeen introduced above in detail. For a person of ordinary skill in theart, the specific implementation and the application range will changeaccording to the idea of the embodiments of the specific implementation.In conclusion, the content of the specification should not be understoodas the limitation of the specific implementation.

The invention claimed is:
 1. A method performed by a user equipment(UE), the method comprising: receiving, from a base station, firstconfiguration information for a random access, the first configurationinformation including a first root sequence index and a first cyclicshift value; receiving, from the base station, second configurationinformation for a beam failure recovery, the second configurationinformation including at least one of a second root sequence index and asecond cyclic shift value; generating a preamble for the beam failurerecovery based on the first configuration information and at least oneof the second root sequence index and the second cyclic shift valueincluded in the second configuration information, in case that thesecond configuration information includes at least one of the secondroot sequence index and the second cyclic shift value; and transmittingthe preamble for the beam failure recovery.
 2. The method of claim 1,wherein the preamble for the beam failure recovery is generated based onthe first root sequence index and the second cyclic shift value, in casethat the second configuration information includes the second cyclicshift value without the second root sequence index, and wherein thepreamble for the beam failure recovery is generated based on the secondroot sequence index and the first cyclic shift value, in case that thesecond configuration information includes the second root sequence indexwithout the second cyclic shift value.
 3. The method of claim 1, whereinthe preamble for the beam failure recovery is generated based on thesecond root sequence index and the second cyclic shift value in casethat the second configuration information includes the second rootsequence index and the second cyclic shift value.
 4. The method of claim1, wherein the second configuration information further includes apreamble index.
 5. The method of claim 1, wherein each of the first rootsequence index and the second root sequence index indicates a basic rootsequence used for generating UE-dedicated preamble resources, andwherein each of the first cyclic shift value and the second cyclic shiftvalue indicates a size of a shift on root sequences.
 6. A methodperformed by a base station, the method comprising: generating firstconfiguration information for a random access, the first configurationinformation including a first root sequence index and a first cyclicshift value; transmitting, to a user equipment (UE), the firstconfiguration information; generating second configuration informationfor a beam failure recovery, the second configuration informationincluding at least one of a second root sequence index and a secondcyclic shift value; transmitting, to the UE, the second configurationinformation to configure a preamble for the beam failure recovery; andreceiving the preamble for the beam failure recovery, wherein thepreamble is generated based on the first configuration information andat least one of the second root sequence index and the second cyclicshift value included in the second configuration information, in casethat the second configuration information includes at least one of thesecond root sequence index and the second cyclic shift value.
 7. Themethod of claim 6, wherein the preamble for the beam failure recovery isgenerated based on the first root sequence index and the second cyclicshift value, in case that the second configuration information includesthe second cyclic shift value without the second root sequence index,and wherein the preamble for the beam failure recovery is generatedbased on the second root sequence index and the first cyclic shiftvalue, in case that the second configuration information includes thesecond root sequence index without the second cyclic shift value.
 8. Themethod of claim 6, wherein the preamble for the beam failure recovery isgenerated based on the second root sequence index and the second cyclicshift value in case that the second configuration information includesthe second root sequence index and the second cyclic shift value.
 9. Themethod of claim 6, wherein the second configuration information furtherincludes a preamble index.
 10. The method of claim 6, wherein each ofthe first root sequence index and the second root sequence indexindicates a basic root sequence used for generating UE-dedicatedpreamble resources, and wherein each of the first cyclic shift value andthe second cyclic shift value indicates a size of a shift on rootsequences.
 11. A user equipment (UE), the UE comprising: a transceiver;and a controller coupled with the transceiver and configured to controlto: receive, from a base station, first configuration information for arandom access, the first configuration information including a firstroot sequence index and a first cyclic shift value, receive, from thebase station, second configuration information for a beam failurerecovery, the second configuration information including at least one ofa second root sequence index and a second cyclic shift value, generate apreamble for the beam failure recovery based on the first configurationinformation and at least one of the second root sequence index and thesecond cyclic shift value included in the second configurationinformation, in case that the second configuration information includesat least one of the second root sequence index and the second cyclicshift value, and transmit the preamble for the beam failure recovery.12. The UE of claim 11, wherein the preamble for the beam failurerecovery is generated based on the first root sequence index and thesecond cyclic shift value, in case that the second configurationinformation includes the second cyclic shift value without the secondroot sequence index, and wherein the preamble for the beam failurerecovery is generated based on the second root sequence index and thefirst cyclic shift value, in case that the second configurationinformation includes the second root sequence index without the secondcyclic shift value.
 13. The UE of the claim 11, wherein the preamble forthe beam failure recovery is generated based on the second root sequenceindex and the second cyclic shift value in case that the secondconfiguration information includes the second root sequence index andthe second cyclic shift value.
 14. The UE of claim 11, wherein thesecond configuration information further includes a preamble index. 15.The UE of claim 11, wherein each of the first root sequence index andthe second root sequence index indicates a basic root sequence used forgenerating UE-dedicated preamble resources, and wherein each of thefirst cyclic shift value and the second cyclic shift value indicates asize of a shift on root sequences.
 16. A base station, the base stationcomprising: a transceiver; and a controller coupled with the transceiverand configured to control to: generate first configuration informationfor a random access, the first configuration information including afirst root sequence index and a first cyclic shift value, transmit, to auser equipment (UE), the first configuration information, generatesecond configuration information for a beam failure recovery, the secondconfiguration information including at least one of a second rootsequence index and a second cyclic shift value, transmit, to the UE, thesecond configuration information to configure a preamble for the beamfailure recovery, and receive the preamble for the beam failurerecovery, wherein the preamble is generated based on the firstconfiguration information and at least one of the second root sequenceindex and the second cyclic shift value included in the secondconfiguration information, in case that the second configurationinformation includes at least one of the second root sequence index andthe second cyclic shift value.
 17. The base station of claim 16, whereinthe preamble for the beam failure recovery is generated based on thefirst root sequence index and the second cyclic shift value, in casethat the second configuration information includes the second cyclicshift value without the second root sequence index, and wherein thepreamble for the beam failure recovery is generated based on the secondroot sequence index and the first cyclic shift value, in case that thesecond configuration information includes the second root sequence indexwithout the second cyclic shift value.
 18. The base station of claim 16,wherein the preamble for the beam failure recovery is generated based onthe second root sequence index and the second cyclic shift value in casethat the second configuration information includes the second rootsequence index and the second cyclic shift value.
 19. The base stationof claim 16, wherein the second configuration information furtherincludes a preamble index.
 20. The base station of claim 16, whereineach of the first root sequence index and the second root sequence indexindicates a basic root sequence used for generating UE-dedicatedpreamble resources, and wherein each of the first cyclic shift value andthe second cyclic shift value indicates a size of a shift on rootsequences.